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1

Hypolocomotion, asymmetrically directed behaviors (licking, lifting, flinching, and shaking) and dynamic weight bearing (gait) changes are not measures of neuropathic pain in mice  

PubMed Central

Background Spontaneous (non-evoked) pain is a major clinical symptom of neuropathic syndromes, one that is understudied in basic pain research for practical reasons and because of a lack of consensus over precisely which behaviors reflect spontaneous pain in laboratory animals. It is commonly asserted that rodents experiencing pain in a hind limb exhibit hypolocomotion and decreased rearing, engage in both reflexive and organized limb directed behaviors, and avoid supporting their body weight on the affected side. Furthermore, it is assumed that the extent of these positive or negative behaviors can be used as a dependent measure of spontaneous chronic pain severity in such animals. In the present study, we tested these assumptions via blinded, systematic observation of digital video of mice with nerve injuries (chronic constriction or spared nerve injury), and automated assessment of locomotor behavior using photocell detection and dynamic weight bearing (i.e., gait) using the CatWalk® system. Results We found no deficits in locomotor activity or rearing associated with neuropathic injury. The frequency of asymmetric (ipsilaterally directed) behaviors were too rare to be seriously considered as representing spontaneous pain, and in any case did not statistically exceed what was blindly observed on the contralateral hind paw and in control (sham operated and unoperated) mice. Changes in dynamic weight bearing, on the other hand, were robust and ipsilateral after spared nerve injury (but not chronic constriction injury). However, we observed timing, pharmacological, and genetic dissociation of mechanical allodynia and gait alterations. Conclusions We conclude that spontaneous neuropathic pain in mice cannot be assessed using any of these measures, and thus caution is warranted in making such assertions.

2010-01-01

2

Aging and partial body weight support affects gait variability  

Microsoft Academic Search

BACKGROUND: Aging leads to increases in gait variability which may explain the large incidence of falls in the elderly. Body weight support training may be utilized to improve gait in the elderly and minimize falls. However, before initiating rehabilitation protocols, baseline studies are needed to identify the effect of body weight support on elderly gait variability. Our purpose was to

Anastasia Kyvelidou; Max J Kurz; Julie L Ehlers; Nicholas Stergiou

2008-01-01

3

Design and validation of GCH System 1.0 which measures the weight-bearing exerted on forearm crutches during aided gait.  

PubMed

Normally, when the patient's functional recovery involves partial weight-bearing aided walking using forearm crutches, it is not possible to control the amount of weight-bearing objectively that the individuals carry out and its progression. This leads to significant errors in accuracy and, consequently, complications and after effects in pathologies. To compensate for this deficiency, we have set out to design and validate a measurement system and a computerized record of the loads exerted on Canadian crutches in aided walking as well as incorporating a mechanism for acoustic and visual biofeedback that will inform the subject if said charges are correct, so that they are able correct their errors and avoid problems in their recovery. We analyzed the validity and reliability of the system through a concordance study with the AMTI OR6-7-2000 force plate, extensively validated previously, while finding a correlation coefficient of 0.99 with a significance (p<0.001). We have designed and developed a measurement system with a computerized record, analysis and wireless graphical display of real-time data, incorporating a mechanism for acoustic and visual biofeedback to measure the loads exerted on forearm crutches during aided walking. The device, called "GCH System 1.0" is a reliable and valid instrument. PMID:23218725

Chamorro Moriana, Gema; Roldán, Jesús Rebollo; Rejano, José Jesús Jiménez; Martínez, Raquel Chillón; Serrano, Carmen Suárez

2013-04-01

4

Calf stretching in non-weight bearing versus weight bearing.  

PubMed

Limited ankle dorsiflexion passive range of motion (DF PROM) has been associated with lower extremity overuse injuries. Therefore, clinicians often prescribe stretching exercises to increase ankle DF PROM. However, there is limited evidence to indicate if any particular gastrocnemius stretching exercise results in greater improvement in DF PROM. The aim of this study was to determine if gastrocnemius stretching in non-weight bearing (NWB) or weight bearing (WB) results in a greater increase of ankle DF PROM. 28 healthy volunteers, aged 18-55 years, who exhibited less than 10 degrees of ankle DF PROM completed the study. Participants were randomized into 2 stretching groups: NWB and WB. Both groups completed a 3-week home gastrocnemius stretching program, consisting of 5 repetitions held for 30 s each, 2 times daily. Participants' ankle DF PROM was measured with a blinded standard goniometer in NWB and WB positions before and after participation in a 3-week home gastrocnemius stretching program. Two 3-way mixed model ANOVAs demonstrated no significant difference in ankle DF PROM between the NWB and WB groups for either the NWB measurement condition (p=0.49) or WB measurement condition (p=0.86). Gastrocnemius stretching exercises performed in NWB or WB were equally effective in increasing ankle DF PROM. PMID:21181639

Dinh, N V; Freeman, H; Granger, J; Wong, S; Johanson, M

2011-03-01

5

Fixed-Bearing Total Ankle Replacement (TAR) Improves Gait Function  

MedlinePLUS

... positive short-term results A study of gait mechanics in patients who underwent total ankle replacement (TAR) ... improvement in nearly all measured parameters of gait mechanics (measured preoperatively, 1 year postoperative, and 2 years ...

6

Measuring Bearing Wear Via Weight Loss  

NASA Technical Reports Server (NTRS)

Wear in critical parts of bearings measured via amounts of weight lost during use. Technique applicable in general to bearings made of nonporous materials. Weight-loss measurements easier, faster, more precise, and less likely to damage measured parts. Weight-loss measurements performed in clean rooms and under constraint of extreme cleanliness for compatability with liquid oxygen.

Keba, John E.; Moore, Richard S.

1989-01-01

7

Aging and partial body weight support affects gait variability  

PubMed Central

Background Aging leads to increases in gait variability which may explain the large incidence of falls in the elderly. Body weight support training may be utilized to improve gait in the elderly and minimize falls. However, before initiating rehabilitation protocols, baseline studies are needed to identify the effect of body weight support on elderly gait variability. Our purpose was to determine the kinematic variability of the lower extremities in young and elderly healthy females at changing levels of body weight support during walking. Methods Ten young and ten elderly females walked on a treadmill for two minutes with a body weight support (BWS) system under four different conditions: 1 g, 0.9 g, 0.8 g, and 0.7 g. Three-dimensional kinematics was captured at 60 Hz with a Peak Performance high speed video system. Magnitude and structure of variability of the sagittal plane angular kinematics of the right lower extremity was analyzed using both linear (magnitude; standard deviations and coefficient of variations) and nonlinear (structure; Lyapunov exponents) measures. A two way mixed ANOVA was used to evaluate the effect of age and BWS on variability. Results Linear analysis showed that the elderly presented significantly more variability at the hip and knee joint than the young females. Moreover, higher levels of BWS presented increased variability at all joints as found in both the linear and nonlinear measures utilized. Conclusion Increased levels of BWS increased lower extremity kinematic variability. If the intent of BWS training is to decrease variability in gait patterns, this did not occur based on our results. However, we did not perform a training study. Thus, it is possible that after several weeks of training and increased habituation, these initial increased variability values will decrease. This assumption needs to be addressed in future investigation with both "healthy" elderly and elderly fallers. In addition, it is possible that BWS training can have a positive transfer effect by bringing overground kinematic variability to healthy normative levels, which also needs to be explored in future studies.

Kyvelidou, Anastasia; Kurz, Max J; Ehlers, Julie L; Stergiou, Nicholas

2008-01-01

8

The effect of partial weight bearing in a walking boot on plantar pressure distribution and center of pressure.  

PubMed

Physicians routinely prescribe partial weight bearing in a walking boot following fractures of the lower limbs in order to produce the needed mechanical environment to facilitate healing. Plantar pressure measurements can provide key information regarding the mechanical environment experienced by lower limb bones. The effect of walking boots on plantar pressure distribution has been well reported, however, the combined effects of partial weight bearing and walking boots on plantar pressure distribution and center of pressure is unknown. Thirteen healthy volunteers with no known gait pathologies were fitted with a multi-pressure sensor insole that recorded their plantar pressure distribution during four walking trials: (i) normal walking, (ii) full weight bearing in a walking boot, (iii) 27 kg partial weight bearing in a walking boot and (iv) 9 kg partial weight bearing in a walking boot. Results demonstrated that changing from trial (i) to (iv) resulted in a posterior shift in weight distribution; the percentage of total weight experienced at the heel increased while the percentage of total weight experienced at the forefoot (both medial and lateral) and the hallux decreased. Center of pressure trajectories also shifted more posteriorly. Additionally, while in a walking boot the gait during full and partial weight bearing resulted in more even foot loading. PMID:22633830

North, Kylee; Potter, Michael Q; Kubiak, Erik N; Bamberg, Stacy J Morris; Hitchcock, Robert W

2012-07-01

9

Weight distribution and gait in dairy cattle are affected by milking and late pregnancy.  

PubMed

There is increased interest in automated methods for lameness detection, such as measures of weight distribution. Still, practical use of such methods depends on knowing the conditions that affect how cows distribute their weight. In 3 experiments, 10, 18, and 12 Holstein cows were trained to stand on a platform that measured the weight placed on each of their legs. The objectives were to evaluate how cows change their weight distribution after milking, after calving, and when standing with the front legs elevated and to evaluate the effect of the udder fill and fetus weight on the gait score. Comparisons before and after milking and before and after calving showed that the weight of milk was carried mainly on the back legs, whereas the weight of the fetus was distributed between front (52%) and back legs (48%). The percentage of weight distributed between front and back legs was not affected by elevation of the front legs. Weight shifting between contralateral legs was greater before calving than after; the weight variability over time decreased by 30% after calving. A full udder increased gait score by 0.3 +/- 0.1 and particularly abduction/adduction of the back legs (increased by 83%). Gait score did not change after calving, although the back arch increased by 25%. Therefore, time since milking and state of late pregnancy need consideration when using gait score and measures of weight distribution to detect lameness. PMID:19164668

Chapinal, N; de Passillé, A M; Rushen, J

2009-02-01

10

Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises.  

PubMed

Study Design Single-group, repeated-measures design. Objective To compare patellofemoral joint (PFJ) stress among weight-bearing and non-weight-bearing quadriceps exercises. Background An important consideration when prescribing exercises to strengthen the quadriceps in persons with patellofemoral pain is to minimize PFJ loading. Currently, there is disagreement in the literature as to which exercises and ranges of motion best accomplish this goal. Methods Ten healthy subjects participated. Lower extremity kinematics, kinetics, and electromyography of the knee musculature were obtained during a weight-bearing squatting exercise and 2 non-weight-bearing knee extension exercises: (1) knee extension with variable resistance, and (2) knee extension with constant resistance. A previously described biomechanical model was used to estimate PFJ stress at 0°, 15°, 30°, 45°, 60°, 75°, and 90° of knee flexion. PFJ stress was compared among the 3 exercises using a 2-way analysis of variance with repeated measures. Results Compared to the 2 non-weight-bearing exercises, the squat exercise produced significantly higher PFJ stress at 90°, 75°, and 60° of knee flexion. Conversely, the 2 non-weight-bearing exercises produced significantly higher PFJ stress at 30°, 15°, and 0° of knee flexion when compared to the squat exercise. The knee-extension-with-variable-resistance exercise produced significantly lower PFJ stress than the knee-extension-with-constant-resistance exercise at 90°, 75°, and 60° of knee flexion. Conclusion To minimize PFJ stress while performing quadriceps exercises, our data suggest that the squat exercise should be performed from 45° to 0° of knee flexion and the knee-extension-with-variable-resistance exercise should be performed from 90° to 45° of knee flexion. J Orthop Sports Phys Ther 2014;44(5):320-327. Epub 27 March 2014. doi:10.2519/jospt.2014.4936. PMID:24673446

Powers, Christopher M; Ho, Kai-Yu; Chen, Yu-Jen; Souza, Richard B; Farrokhi, Shawn

2014-05-01

11

A Gait Generation for an Unlocked Joint Failure of the Quadruped Robot with Balance Weight  

NASA Astrophysics Data System (ADS)

Assurance of a stability margin for a stabilized gait is the most important issue for the quadruped robot. Although various studies for dynamic stability of the quadruped robot have been studied, problems in which one of the legs has an unlocked joint failure haven’t been relatively studied so far. In this paper, assurance of stability margin for the unlocked joint failure of the quadruped robot is suggested by using gait stabilization and a control method of the moment of inertia. Then, efficiency of BW (balance weight) will be experimentally verified by comparing the two types of robot; one is equipped with the BW, the other is not equipped with BW.

Cho, C. H.; Min, B. C.; Kim, D. H.

12

Early weight bearing after lower extremity fractures in adults.  

PubMed

Weight-bearing protocols should optimize fracture healing while avoiding fracture displacement or implant failure. Biomechanical and animal studies indicate that early loading is beneficial, but high-quality clinical studies comparing weight-bearing protocols after lower extremity fractures are not universally available. For certain fracture patterns, well-designed trials suggest that patients with normal protective sensation can safely bear weight sooner than most protocols permit. Several randomized, controlled trials of surgically treated ankle fractures have shown no difference in outcomes between immediate and delayed (?6 weeks) weight bearing. Retrospective series have reported low complication rates with immediate weight bearing following intramedullary nailing of femoral shaft fractures and following surgical management of femoral neck and intertrochanteric femur fractures in elderly patients. For other fracture patterns, particularly periarticular fractures, the evidence in favor of early weight bearing is less compelling. Most surgeons recommend a period of protected weight bearing for patients with calcaneal, tibial plafond, tibial plateau, and acetabular fractures. Further studies are warranted to better define optimal postoperative weight-bearing protocols. PMID:24292929

Kubiak, Erik N; Beebe, Michael J; North, Kylee; Hitchcock, Robert; Potter, Michael Q

2013-12-01

13

The effect of backpack load on the gait of normal adolescent girls  

Microsoft Academic Search

Concerns regarding the effects of load carriage have led to recommendations that backpacks be limited to 10?–?15% of body weight, based on significant changes in physical performance. However, gait responses to backpack loads are not entirely consistent and there is a particular lack of data regarding load-bearing gait in adolescent females. Gait patterns of 22 normal adolescent girls were recorded

Daniel HK Chow; Monica LY Kwok; Alexander CK Au-Yang; Andrew D Holmes; Jack CY Cheng; Fiona YD Yao

2005-01-01

14

Image based weighted center of proximity versus directly measured knee contact location during simulated gait.  

PubMed

To understand the mechanical consequences of knee injury requires a detailed analysis of the effect of that injury on joint contact mechanics during activities of daily living. Three-dimensional (3D) knee joint geometric models have been combined with knee joint kinematics to dynamically estimate the location of joint contact during physiological activities-using a weighted center of proximity (WCoP) method. However, the relationship between the estimated WCoP and the actual location of contact has not been defined. The objective of this study was to assess the relationship between knee joint contact location as estimated using the image-based WCoP method, and a directly measured weighted center of contact (WCoC) method during simulated walking. To achieve this goal, we created knee specific models of six human cadaveric knees from magnetic resonance imaging. All knees were then subjected to physiological loads on a knee simulator intended to mimic gait. Knee joint motion was captured using a motion capture system. Knee joint contact stresses were synchronously recorded using a thin electronic sensor throughout gait, and used to compute WCoC for the medial and lateral plateaus of each knee. WCoP was calculated by combining knee kinematics with the MRI-based knee specific model. Both metrics were compared throughout gait using linear regression. The anteroposterior (AP) location of WCoP was significantly correlated with that of WCoC on both tibial plateaus in all specimens (p<0.01, 95% confidence interval of Pearson?s coefficient r>0), but the correlation was not significant in the mediolateral (ML) direction for 4/6 knees (p>0.05). Our study demonstrates that while the location of joint contact obtained from 3D knee joint contact model, using the WCoP method, is significantly correlated with the location of actual contact stresses in the AP direction, that relationship is less certain in the ML direction. PMID:24837219

Wang, Hongsheng; Chen, Tony; Koff, Matthew F; Hutchinson, Ian D; Gilbert, Susannah; Choi, Dan; Warren, Russell F; Rodeo, Scott A; Maher, Suzanne A

2014-07-18

15

The use of body weight support on ground level: an alternative strategy for gait training of individuals with stroke  

Microsoft Academic Search

BACKGROUND: Body weight support (BWS) systems on treadmill have been proposed as a strategy for gait training of subjects with stroke. Considering that ground level is the most common locomotion surface and that there is little information about individuals with stroke walking with BWS on ground level, it is important to investigate the use of BWS on ground level in

Catarina O Sousa; José A Barela; Christiane L Prado-Medeiros; Tania F Salvini; Ana MF Barela

2009-01-01

16

Determinants of bone density among athletes engaged in weight-bearing and non-weight-bearing activity  

NASA Technical Reports Server (NTRS)

The effect of weight bearing activity on the bone density was investigated in athletes by comparing the measures of bone density of athletes engaged in weight-training programs with those of polo players and nonexercising subjects. All subjects had measurements of spinal trabecular and integral bone density by quantitative tomography, as well as determinations of hip bone density by dual photon absorptiometry. Results confirmed previous findings by Block et al. (1987) of significantly greater bone density among highly trained athletes compared with nonexercising subjects of similar age. Results also indicated that athletes engaged in non-weight-bearing forms of rigorous exercise had greater levels of bone density. However, as the participants in this study were exceptional athletes, engaged in a strenuous sport with both aerobic and heavy resistance components, a confirmation of these data is needed, using larger samples of individuals.

Block, Jon E.; Friedlander, Anne L.; Brooks, George A.; Steiger, Peter; Stubbs, Harrison A.

1989-01-01

17

Using Gait as a Biometric, via Phase-weighted Magnitude Spectra  

Microsoft Academic Search

Abstract. Gait is a ,biometric which ,is subject ,to increasing ,interest. Current approaches,include modelling ,gait as a ,spatio-temporal sequence ,and ,as an articulated model. By considering legs only, gait can be considered to be the motion,of interlinked pendula. We describe how,the Hough transform is used to extract the lines which represent legs in sequences,of video,images. The change in inclination of

David Cunado; Mark S. Nixon; John N. Carter

1997-01-01

18

Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy  

NASA Technical Reports Server (NTRS)

This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

1992-01-01

19

Changes in skeletal muscle gene expression consequent to altered weight bearing  

NASA Technical Reports Server (NTRS)

Skeletal muscle is a dynamic organ that adapts to alterations in weight bearing. This brief review examines changes in muscle gene expression resulting from the removal of weight bearing by hindlimb suspension and from increased weight bearing due to eccentric exercise. Acute (less than or equal to 2 days) non-weight bearing of adult rat soleus muscle alters only the translational control of muscle gene expression, while chronic (greater than or equal to 7 days) removal of weight bearing appears to influence pretranslational, translational, and posttranslational mechanisms of control. Acute and chronic eccentric exercise are associated with alterations of translational and posttranslational control, while chronic eccentric training also alters the pretranslational control of muscle gene expression. Thus alterations in weight bearing influence multiple sites of gene regulation.

Booth, F. W.; Kirby, C. R.

1992-01-01

20

Adaptive body weight support controls human activity during robot-aided gait training  

Microsoft Academic Search

Current clinical practice of robot-aided gait training is not as effective as expected. Cooperative control strategies aim at improving the effectiveness of robot-aided training by empowering patients to participate more actively. Our group has recently proposed the concept of bio-cooperative control, which explicitely considers the role of the human in the loop, as an extension of these strategies. A supervising

Alexander Duschau-Wicke; Simon Felsenstein; Robert Riener

2009-01-01

21

Soleus Fiber Force and Maximal Shortening Velocity After Non-Weight Bearing with Intermittent Activity.  

National Technical Information Service (NTIS)

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type 1 fiber force (in mN), tension (P(sub o); force per fiber cross-sectional area in kN/sq m), and m...

J. J. Widrick J. J. Bangart M. Karhanek R. H. Fitts

1996-01-01

22

Quantitative comparison of plantar foot shapes under different weight-bearing conditions.  

PubMed

Knowledge of the plantar foot shape alteration under weight bearing can offer implications for the design and construction of a comfortable and functional foot support. The purpose of this study was to quantify the change in three-dimensional foot shape under different weight-bearing conditions. The plantar foot shapes of 16 normal feet were collected by an impression casting method under three weight-bearing conditions: non-weight bearing, semi-weight bearing, and full-weight bearing. An optical digitizing system was used to capture the three-dimensional plantar surface shape of the foot cast. Measurements and comparisons from the digitized shapes were conducted for the whole foot and regions of the foot. The data showed that increased weight bearing significantly increased the contact area, foot length, foot width, and rearfoot width, while it decreased average height, arch height, and arch angle. Compared with the non-weight-bearing foot shape, the semi-weight-bearing condition would produce increases in the contact area of 35.1% +/- 21.6 %, foot length of 2.7% +/- 1.2%, foot width of 2.9% +/- 2.4%, and rearfoot width of 5.9% +/- 4.8%, and decreases in the arch height of 15.4% +/- 7.8% and arch angle of 21.7% +/- 17.2%. The full-weight-bearing condition would produce increases in the contact area of 60.4% +/- 33.2%, foot length of 3.4% +/- 1.3%, foot width of 6.0% +/- 2.1%, and rearfoot width of 8.7% +/- 4.9%, and decreases in the arch height of 20.0% +/- 9.2% and arch angle of 41.2% +/- 16.2%. The findings may be useful for considering the change of foot shape in the selection of shoe size and shoe or insole design. PMID:15077664

Tsung, Bonnie Yuk San; Zhang, Ming; Fan, Yu Bo; Boone, David Alan

2003-01-01

23

Weight bearing does not contribute to the development of osteonecrosis of the femoral head  

PubMed Central

The hip joint is one of the major structures in the human body and the resultant force acting through the hip joint is 300% of body weight. Therefore, weight bearing, as a cause of ischaemia, may contribute to the development of non-traumatic osteonecrosis of the femoral head (ONFH). However, it remains unclear whether weight bearing is related to the development of non-traumatic ONFH. Therefore the aim of this study was to clarify the role of weight bearing in the development of non-traumatic ONFH. Non-weight-bearing (NWB) rats were tail suspended to prevent any weight coming to bear on the hindlimbs from day 1 to the time of sacrifice. The weight-bearing (WB) group rats were also housed individually, although without tail suspension. All rats were injected with lipopolysaccharide and methylprednisolone to promote the development of non-traumatic ONFH. All animals were sacrificed three weeks after the final methylprednisolone injection. Histopathological analysis was performed. Osteonecrosis of the femoral head was observed not only in the NWB but also in the WB rats; however, no osteonecrosis of the humeral head was observed in either group. We confirmed that non-traumatic ONFH developed in NWB rats, suggesting that weight bearing does not contribute to the development of non-traumatic ONFH in rats.

Okazaki, Shunichiro; Nagoya, Satoshi; Tateda, Kenji; Katada, Ryuichi; Mizuo, Keisuke; Watanabe, Satoshi; Yamashita, Toshihiko; Matsumoto, Hiroshi

2012-01-01

24

Effect of unaccustomed eccentric exercise on proprioception of the knee in weight and non-weight bearing tasks.  

PubMed

The study investigates the effects of eccentric exercise of the quadriceps on proprioception of the knee in weight and non-weight bearing tasks. Proprioception of the exercised leg was assessed at 120° and 150° of knee extension in 15 healthy adults (age 25.0 ± 3.6 yrs) before, immediately after, and 24h following eccentric exercise of the quadriceps. Three tests of proprioception were performed: 1. matching the position of the exercised leg (right leg) to the reference leg (left leg) in sitting (non-weight bearing matching task); 2. repositioning the exercised leg after active movement in sitting (non-weight bearing repositioning task); 3. repositioning the exercised leg after active movement in standing (weight bearing task). Maximum knee extension force was reduced by 77.0 ± 12.3 % immediately after the exercise, and by 82.7 ± 16.2% 24h post exercise, with respect to baseline (P<0.001). The absolute error in the non-weight bearing matching task at 120° of knee extension was greater immediately following eccentric exercise (12.3 ± 5.6, P<0.001) and 24h after exercise (8.1 ± 4.5, P<0.05) compared to baseline (5.8 ± 2.7). Similarly, the absolute error in the non-weight bearing repositioning task at 120° was greater both immediately (5.9 ± 3.1°, P<0.01) and 24h post exercise (5.2 ± 3.0°, P<0.05) compared to baseline (4.5 ± 2.6°). Therefore, in both non-weight bearing tasks, the subjects matched the position of their leg after eccentric exercise by adopting a more extended knee position of the exercised limb. Furthermore, the subjects showed higher variability in their performance immediately post exercise (P<0.05, compared to baseline) but not 24h after. In contrast, eccentric exercise did not affect the repositioning errors in the weight bearing task. In conclusion, eccentric exercise of the quadriceps impairs proprioception of the knee both immediately after and 24h post exercise, but only in non-weight bearing tasks. PMID:21044850

Vila-Chã, Carolina; Riis, Simone; Lund, Ditte; Møller, Anders; Farina, Dario; Falla, Deborah

2011-02-01

25

Analgesics improve the gait of lame dairy cattle.  

PubMed

Pain associated with injuries of the hoof and surrounding tissues is an important cause of lameness. The objective was to detect the attributes of impaired gait that are associated with pain. In 3 separate experiments, lactating Holstein cows (n = 20; n = 21; n = 27) diagnosed with varying degrees of gait impairment were injected i.m. (Exp. 1 and 2) or i.v. (Exp. 3) with the analgesic ketoprofen at 0, 0.3, 1.5, or 3.0 mg/kg of BW. Gait was evaluated subjectively using a numerical rating system (NRS; varying from 1 to 5) and 6 specific gait attributes (back arch, tracking up, joint flexion, asymmetric steps, head bob, and reluctance to bear weight). Each experiment was divided into 3 phases each lasting 3 d: before treatment, after treatment, and during treatment with daily injections of ketoprofen. The NRS improved by 0.25 +/- 0.05 with the highest dose of ketoprofen. Although none of the specific gait attributes showed a consistent response to treatment, there was an interaction between dose and experiment for asymmetric steps and reluctance to bear weight; in Exp. 1, but not Exp. 2 and 3, cow steps were more symmetrical (improving by 7.16 +/- 1.02), and cows distributed their weight more evenly (improving by 5.84 +/- 1.13) at the highest doses of ketoprofen. These results indicated that the NRS was more sensitive than the specific gait attributes in assessing differences in gait associated with pain. The results showed that ketoprofen has only a modest effect on gait, indicating either that this drug has little effect on pain due to lameness or that much variation in NRS was due to factors other than pain. PMID:18650277

Flower, F C; Sedlbauer, M; Carter, E; von Keyserlingk, M A G; Sanderson, D J; Weary, D M

2008-08-01

26

Gait Shape Estimation for Identification  

Microsoft Academic Search

A method is presented for identifying individuals by shape, given a sequence of noisy silhouettes segmented from video. A spectral partitioning framework is used to cluster similar poses and automatically extract gait shapes. The method uses a variance-weighted similarity met- ric to induce clusters that cover disparate stages in the gait cycle. This technique is applied to the HumanID Gait

David Tolliver; Robert T. Collins

2003-01-01

27

Correlation of psychomotor findings and the ability to partially weight bear  

PubMed Central

Background Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test. Methods 50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction. Results The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously. Conclusions The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits.

2012-01-01

28

Seismic velocities for hydrate-bearing sediments using weighted equation  

NASA Astrophysics Data System (ADS)

A weighted equation based on the three-phase time-average and Wood equations is applied to derive a relationship between the compressional wave (P wave) velocity and the amount of hydrates filling the pore space. The proposed theory predicts accurate P wave velocities of marine sediments in the porosity range of 40-80% and provides a practical means of estimating the amount of in situ hydrate using seismic velocity. The shear (S) wave velocity is derived under the assumption that the P to S wave velocity ratio of the hydrated sediments is proportional to the weighted average of the P to S wave velocity ratios of the constituent components of the sediment. In the case that all constituent components are known, a weighted equation using multiphase time-average and Wood equations is possible. However, this study showed that a three-phase equation with modified matrix velocity, compensated for the clay content, is sufficient to accurately predict the compressional wave velocities for the marine sediments. This theory was applied to the laboratory measurements of the P and S wave velocities in permafrost samples to infer the amount of ice in the unconsolidated sediment. The results are comparable to the results obtained by repeatedly applying the two-phase wave scattering theory. The theory predicts that the Poisson's ratio of the hydrated sediments decreases as the hydrate concentration increases and the porosity decreases. In consequence, the amplitude versus offset (AVO) data for the bottom-simulating reflections may reveal positive, negative, or no AVO anomalies depending on the concentration of hydrates in the sediments.

Lee, M. W.; Hutchinson, D. R.; Collett, T. S.; Dillon, W. P.

1996-09-01

29

Evaluation of medial meniscus tears and meniscal stability: weight-bearing MRI vs arthroscopy.  

PubMed

To assess the role of dedicated low-field standard and weight-bearing MRI in the evaluation of stable or unstable tears of medial meniscus in comparison with arthroscopy. Our series included 1750 knee MRI scans performed with a high-field MRI scanner from July 2010 to August 2011. We retrospectively reviewed and analyzed 20 MRI exams of normal knee and 57 MRI exams of knee with clinical evidence of tears of the medial meniscus. In the same session, after conventional 1.5T and "dedicated" 0.25T supine MRI exam, the patients underwent weight-bearing examination with the same dedicated MRI unit. In all cases sagittal and coronal PD-W were used. All patients underwent arthroscopy 18-25 days after the weight-bearing MRI. In the first group, no statistically significant anatomical modifications of shape, intensity and position of the medial meniscus between standard 1.5T, dedicated supine and upright MRI were observed. In group A, the images acquired in the supine position (dedicated and 1.5T MRI) documented in 21 cases a traumatic tear (group 2A) and in 36 cases a degenerative tear (group 2B). In group 2A, weight-bearing MRI showed presence of unstable tear a degenerative unstable meniscal tear only in 19 out of 36 cases. In group 2B, weight-bearing MRI showed only in 9 out 21 cases. Arthroscopy confirmed weight-bearing MRI diagnosis in all cases. This new approach to meniscus pathology gives an important contribution to a better management of a diagnostic-therapeutic approach in which standard MRI has not played a key role, so far. PMID:23199751

Barile, Antonio; Conti, Laura; Lanni, Giuseppe; Calvisi, Vittorio; Masciocchi, Carlo

2013-04-01

30

Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.  

ERIC Educational Resources Information Center

Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None…

Terrio, Kate; Auld, Garry W.

2002-01-01

31

Gender Comparison of Patellar Tendon Tibial Shaft Angle with Weight Bearing  

Microsoft Academic Search

The objective of this study was to compare the patellar tendon tibial shaft angle at specific angles of knee flexion in young male and female athletes with lower extremity weight-bearing to determine if a gender difference exists. Twenty healthy recreational athletes (10 males and 10 females) aged 22 to 28 years with normal knees were recruited. Seven lateral radiographs of

Ryan M. Nunley; Donna Wright; Jordan B. Renner; Bing Yu; William E. Garrett Jr

2003-01-01

32

Immediate full-weight-bearing mobilisation for repaired Achilles tendon ruptures: a pilot study  

Microsoft Academic Search

Recent experimental and clinical evidence suggests that early loading and mobilisation for Achilles tendon ruptures may improve functional outcomes. This paper presents the results of a pilot study designed to assess the safety of immediate weight-bearing mobilisation. Twenty-eight operatively repaired patients were randomised to either immediate loading in an orthosis or traditional serial plaster casting. An independent observer, blinded to

M. L. Costa; L. Shepstone; C. Darrah; T. Marshall; S. T. Donell

2003-01-01

33

Impact of pregnancy and obesity on cardiorespiratory responses during weight-bearing exercise  

Microsoft Academic Search

The present study is the first to compare the cardiorespiratory responses during progressive weight-bearing treadmill exercise in normal-weight non-pregnant (NP, n=14), normal-weight pregnant (PG, n=20) and obese pregnant (PGOB, n=20) women. Exercise duration and peak treadmill speed were lower in PG (23.9±4.9min; 1.6±0.2m\\/s; P<0.001) compared to NP (33.7±4.9min; 2.0±0.2m\\/s) and were further reduced in PGOB (19.6±2.8min; 1.4±0.1m\\/s; P<0.001) indicating a

Margie H. Davenport; Craig D. Steinback; Michelle F. Mottola

2009-01-01

34

Evaluation of the 3-dimensional, weight-bearing orientation of the normal adult knee.  

PubMed

The purpose of this study was to use 3-dimensional, weight-bearing images corrected for rotation to establish normative data of limb alignment and joint line orientation in asymptomatic, adult knees. One hundred adults (200 lower extremities) were recruited to receive weight-bearing, simultaneous biplanar imaging of both lower extremities. Multiple radiographic parameters were measured from 3D images, corrected for limb rotation. 70.0% of knees were in neutral, 19.5% in varus, and 10.5% in valgus overall alignment. Only 31 % of knees possessed both a neutral mechanical axis and the absence of joint line obliquity. There was substantial agreement between the 2D and 3D images for overall mechanical alignment (?=0.77), but only a moderate agreement for joint line obliquity (?=0.58). A substantial portion of asymptomatic adults possess either a varus or valgus mechanical alignment and joint line obliquity. PMID:24315446

Nam, Denis; Shah, Ritesh R; Nunley, Ryan M; Barrack, Robert L

2014-05-01

35

Static versus dynamic prosthetic weight bearing in elderly trans-tibial amputees  

Microsoft Academic Search

The purpose of this study was to compare prosthetic weight-bearing tolerance in the standing position to the dynamic vertical ground reaction forces (VGRF) experienced during walking in elderly dysvascular trans-tibial amputees. Ten unilateral trans-tibial amputees attending an amputee clinic (mean age =67±6.5 years) were selected as subjects. Selection criteria were the level of amputation, age, medical fitness to participate and

M. E. JONES; J. R. STEEL; G. M. BASHFORD; I. R. DAVIDSON

1997-01-01

36

THE EFFECTS OF PARTICULATE POLYETHYLENE AT A WEIGHT-BEARING BONE-IMPLANT INTERFACE  

Microsoft Academic Search

n ten male rats we inserted ceramic 'drawing-pin' implants in weight-bearing positions within the right proximal tibia. Two animals were killed 6 weeks after surgery and two more 14 weeks after surgery. The remaining six received intra-articular injections of either high-density polyethylene (4 rats) or saline (2 rats) at 8, 10 and 12 weeks after surgery. These animals were killed

MATTHEW ALLEN; FRANCESCA BRETT; PETER MILLETT; NEIL RUSHTON

37

Patellofemoral joint contact area increases with knee flexion and weight-bearing.  

PubMed

Patellofemoral pain is a common and debilitating disorder. Elevated cartilage stress of the patellofemoral joint is hypothesized to play a role in the onset of pain. Estimating cartilage stress requires accurate measurements of contact area. The purpose of this study was to estimate patellofemoral joint contact areas in a group of healthy, pain-free subjects during upright, weight-bearing conditions. Sixteen subjects (8 female, 8 male) were scanned in a GE Signa SP open configuration MRI scanner, which allowed subjects to stand or squat while reclining 25 degrees from vertical with the knee positioned at 0 degrees , 30 degrees , or 60 degrees of flexion. A custom-built backrest enabled subjects to be scanned without motion artifact in both weight-bearing (0.45 body weight per leg) and reduced loading conditions ('unloaded' at 0.15 body weight) at each knee flexion posture. Male subjects displayed mean unloaded patellofemoral joint contact areas of 210, 414, and 520 mm(2) at 0 degrees , 30 degrees and 60 degrees of knee flexion, respectively. Female subjects' unloaded contact areas were similar at full extension (0 degrees ), but significantly smaller at 30 degrees and 60 degrees (p<0.01), with mean values of 269 and 396 mm(2), respectively. When normalized by patellar dimensions (heightxwidth), contact areas were not different between genders. Under weight-bearing conditions, contact areas increased by an average of 24% (p<0.05). This study highlights the differences in patellofemoral joint contact area between gender, knee flexion postures, and physiologic loading conditions. PMID:15734247

Besier, Thor F; Draper, Christine E; Gold, Garry E; Beaupré, Gary S; Delp, Scott L

2005-03-01

38

Initial non-weight-bearing therapy is important for preventing vertebral body collapse in elderly patients with clinical vertebral fractures  

PubMed Central

Purpose The aim of the present conventional observational study was to compare the clinical outcomes of initial non-weight-bearing therapy and conventional relative rest therapy among elderly patients with clinical vertebral fractures. Methods In total, 196 consecutive patients with clinical vertebral fractures (mean age: 78 years) who were hospitalized for treatment between January 1999 and March 2007 were analyzed. Initial non-weight-bearing therapy consisted of complete bed rest allowing rolling on the bed without any weight-bearing to the spine for 2 weeks, followed by rehabilitation wearing a soft brace. The indications for initial non-weight-bearing therapy were vertebral fracture involving the posterior portion of the vertebral body at the thoraco-lumbar spine, mild neurological deficit, instability of the fracture site, severe pain, multiple vertebral fractures arising from trauma, malalignment at the fracture site, and mild spinal canal stenosis caused by the fracture. Patients who met the indication criteria were treated with initial non-weight-bearing therapy (n = 103), while the other patients were treated with conventional relative rest (n = 93). All the patients were uniformly treated with intramuscular elcatonin to relieve pain. The primary endpoint was progression of the vertebral fracture. The secondary endpoints included bony union and subjective back pain. The follow-up period was 12 weeks. Results Compared with the conventional relative rest group, the collapse rate of the anterior and posterior portions of the vertebral body was significantly smaller in the initial non-weight-bearing group. The bony union rate was 100% in the initial non-weight-bearing group and 97% in the conventional relative rest group. The number of patients who experienced back pain was significantly lower in the initial non-weight-bearing group than in the conventional relative rest group. Conclusion These results suggest that initial non-weight-bearing therapy is important for preventing vertebral body collapse and for relieving pain among elderly patients with clinical vertebral fractures.

Kishikawa, Yoichi

2012-01-01

39

Early Weight-bearing Using Percutaneous External Fixator for Calcaneal Fracture  

PubMed Central

Calcaneal fracture, the most common tarsal bone fracture, occurs predominantly in manual labors and subsequently has got considerable socioeconomic implications. Treatment modality which can offer early weight bearing and early return to work is therefore needed for those patients. We have used a biplanar percutaneous external fixator for treating calcaneal fractures without operative and per operative visualization of the fractures. We have treated 17 calcaneal fractures in 16 patients, 12 intra articular and five extra articular, with our percutaneous external fixator system without preoperative X-ray control or reduction. Functional outcome was measured using the American Orthopaedic Foot and ankle society Hind foot score. All fractures united with a mean of 55 days. Partial weight bearing was possible in a mean of 1.8 days and full bearing was possible in a mean of 11.6 days. All the patients were returned to their original work within six weeks. Minor infectious complications occurred in 17.6 percent of cases. The average AOFAS score at six months follow up was 83.8. We conclude that our percutaneous external fixator technique for fracture calcaneum is an effective alternative to the currently available – surgical and conservative treatment modalities especially in lower socio economic labor population who need to return to their job as early as possible. Level of Evidence – IV Case series.

Sengodan, Vetrivel Chezian; Sengodan, Mugundhan Moongilpatti

2012-01-01

40

Is Weight-Bearing Asymmetry Associated with Postural Instability after Stroke? A Systematic Review  

PubMed Central

Introduction. Improvement of postural stability is an important goal during poststroke rehabilitation. Since weight-bearing asymmetry (WBA) towards the nonparetic leg is common, training of weight-bearing symmetry has been a major focus in post-stroke balance rehabilitation. It is assumed that restoration of a more symmetrical weight distribution is associated with improved postural stability. Objective. To determine to what extent WBA is associated with postural instability in people after stroke. Methods. Electronic databases were searched (Cochrane, MEDLINE, EMBASE, and CINAHL) until March 2012. Main Eligibility Criteria. (1) Participants were people after stroke. (2) The association between WBA and postural stability was reported. Quality of reporting was assessed with the STROBE checklist and a related tool for reporting of confounding. Results. Nine observational studies met all criteria. Greater spontaneous WBA was associated with higher center of pressure (COP) velocity and with poorer synchronization of COP trajectories between the legs (two and one studies, resp.). Evidence for associations between WBA and performance on clinical balance tests or falls was weak. Conclusion. Greater WBA after stroke was associated with increased postural sway, but the current literature does not provide evidence for a causal relationship. Further studies should investigate whether reducing WBA would improve postural stability.

Kamphuis, Jip F.; Geurts, Alexander C. H.

2013-01-01

41

Prospective, Blinded, Randomized Crossover Study of Gait Rehabilitation in Stroke Patients Using the Lokomat Gait Orthosis  

Microsoft Academic Search

Objective. Treadmill training with partial body weight support has been suggested as a useful strategy for gait rehabilitation after stroke. This prospective, blinded, randomized controlled study of gait retraining tested the feasibility and potential effi- cacy of using an electromechanical-driven gait orthosis (Lokomat) for treadmill training. Methods. Sixteen stroke patients, mostly within 3 months after onset, were random- ized into

Andreas Mayr; Markus Kofler; Ellen Quirbach; Heinz Matzak; Katrin Fröhlich; Leopold Saltuari

42

Magnetic resonance imaging evaluation of weight-bearing subchondral trabecular bone in the knee  

PubMed Central

Objective Changes in weight-bearing subchondral bone are central to osteoarthritis (OA) pathophysiology. Using MR, knee trabecular bone is typically assessed in the axial plane, however partial volume artifacts limit the utility of MR methods for femorotibial compartment subchondral bone analysis. Oblique-coronal acquisitions may enable direct visualization and quantification of the expected increases in femorotibial subchondral trabecular bone. Methods MR acquisition parameters were first optimized at 3 Tesla. Thereafter, five volunteers underwent axial and coronal exams of their right knee. Each image series was evaluated visually and quantitatively. An anatomically standardized region-of-interest was placed on both the medial and lateral tibial plateaus of all coronal slices containing subchondral bone. Mean and maximum marrow signal was measured, and “bone signal” was calculated. Results The MR acquisition had spatial resolution 0.2× 0.2×1.0 mm and acquisition time 10.5 min. The two asymptomatic knees exhibited prominent horizontal trabeculae in the tibial subchondral bone, while the one confirmed OA knee had disorganized subchondral bone and absent horizontal trabeculae. The subchondral bone signal was 8–14% higher in both compartments of the OA knee than the asymptomatic knees. Conclusion The weight-bearing femorotibial subchondral trabecular bone can be directly visualized and changes quantified in the coronal-oblique plane. Qualitative and quantitative assessments can be performed using the resultant images and may provide a method to discriminate between the healthy and OA knees. These methods should enable a quantitative evaluation of the role of weight-bearing subchondral bone in the natural history of knee OA to be undertaken.

Lo, Grace H.; Sloane, Gretchen; Fanella, Lynn; Hunter, David J.; Eaton, Charles B.; McAlindon, Timothy E.

2014-01-01

43

Non-weight-bearing neural control of a powered transfemoral prosthesis  

PubMed Central

Lower limb prostheses have traditionally been mechanically passive devices without electronic control systems. Microprocessor-controlled passive and powered devices have recently received much interest from the clinical and research communities. The control systems for these devices typically use finite-state controllers to interpret data measured from mechanical sensors embedded within the prosthesis. In this paper we investigated a control system that relied on information extracted from myoelectric signals to control a lower limb prosthesis while amputee patients were seated. Sagittal plane motions of the knee and ankle can be accurately (>90%) recognized and controlled in both a virtual environment and on an actuated transfemoral prosthesis using only myoelectric signals measured from nine residual thigh muscles. Patients also demonstrated accurate (~90%) control of both the femoral and tibial rotation degrees of freedom within the virtual environment. A channel subset investigation was completed and the results showed that only five residual thigh muscles are required to achieve accurate control. This research is the first step in our long-term goal of implementing myoelectric control of lower limb prostheses during both weight-bearing and non-weight-bearing activities for individuals with transfemoral amputation.

2013-01-01

44

Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers.  

PubMed

The effects of 14 days of spaceflight (SF) or hindlimb suspension (HS) (Cosmos 2044) on myosin heavy chain (MHC) isoform content of the rat soleus muscle and single muscle fibers were determined. On the basis of electrophoretic analyses, there was a de novo synthesis of type IIx MHC but no change in either type I or IIa MHC isoform proportions after either SF or HS compared with controls. The percentage of fibers containing only type I MHC decreased by 26 and 23%, and the percentage of fibers with multiple MHCs increased from 6% in controls to 32% in HS and 34% in SF rats. Type IIx MHC was always found in combination with another MHC or combination of MHCs; i.e., no fibers contained type IIx MHC exclusively. These data suggest that the expression of the normal complement of MHC isoforms in the adult rat soleus muscle is dependent, in part, on normal weight bearing and that the absence of weight bearing induces a shift toward type IIx MHC protein expression in the preexisting type I and IIa fibers of the soleus. PMID:9018504

Talmadge, R J; Roy, R R; Edgerton, V R

1996-12-01

45

Effects of immobilization on rat hind limb muscles under non-weight-bearing conditions  

NASA Technical Reports Server (NTRS)

The effect of stretched and unstretched immobilization of a hind limb on the concentration and the metabolism of proteins in the hind-limb muscles of rats was investigated. The animals were divided into three groups: (1) weight-bearing controls, (2) tail-cast-suspended, and (3) suspended, with one hind limb immobilized with the ankle in dorsiflexion (30-40 deg angle) and the other freely moving. It was found that unloading the hind limbs for 6 days by tail cast suspension caused soleus to atrophy and reduced growth of the gastrocnemius and plantaris muscles; unloading resulted in a higher degradation rate and lower synthesis rate in both in vitro and in vivo. Chronic stretch of the unloaded soleus not only prevented its atrophy but led to significant hypertrophy, relative to weight-bearing controls, with increases in both the sarcoplasmic and myofibrillar protein fractions. Immobilizing one ankle in dorsiflexion prevented the inhibition of growth in the plantaris and gastrocnemius muscles due to unloading.

Jaspers, Stephen R.; Fagan, Julie M.; Satarug, Soisungwan; Cook, Paul H.; Tischler, Marc E.

1988-01-01

46

Alterations of collagen matrix in weight-bearing bones during skeletal unloading  

NASA Technical Reports Server (NTRS)

Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the former to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect.

Shiiba, M.; Arnaud, S. B.; Tanzawa, H.; Uzawa, K.; Yamauchi, M.

2001-01-01

47

Early weight-bearing after periacetabular osteotomy leads to a high incidence of postoperative pelvic fractures  

PubMed Central

Background It has not been shown whether accelerated rehabilitation following periacetabular osteotomy (PAO) is effective for early recovery. The purpose of this retrospective study was to compare complication rates in patients with standard and accelerated rehabilitation protocols who underwent PAO. Methods Between January 2002 and August 2011, patients with a lateral center-edge (CE) angle of?weight-bearing with two crutches started 2 months postoperatively in 73 patients (80 hips) with the standard rehabilitation protocol. In 65 patients (76 hips) with the accelerated rehabilitation protocol, postoperative strengthening of the hip, thigh and core musculature was begun on the day of surgery as tolerated. The exercise program included active hip range of motion, and gentle isometric hamstring and quadriceps muscle sets; these exercises were performed for 30 minutes in the morning and 30 minutes in the afternoon with a physical therapist every weekday for 6 weeks. Full weight-bearing with two axillary crutches started on the day of surgery as tolerated. Complications were evaluated for 2 years. Results The clinical results at the time of follow-up were similar in the two groups. The average periods between the osteotomy and full-weight-bearing walking without support were 4.2 months and 6.9 months in patients with the accelerated and standard rehabilitation protocols (P?

2014-01-01

48

Soleus Fiber Force and Maximal Shortening Velocity After Non-Weight Bearing with Intermittent Activity  

NASA Technical Reports Server (NTRS)

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type 1 fiber force (in mN), tension (P(sub o); force per fiber cross-sectional area in kN/sq m), and maximal unloaded shortening velocity (V(sub o), in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca(2+) activation, after which type 1 fiber myosin heavy-chain composition was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type 1 fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in V(sub o) (+33%). In addition, NWB induced a 16% reduction in type 1 fiber P., a 41% reduction in type 1 fiber peak elastic modulus [E(sub o), defined as ((delta)force/(delta)length x (fiber length/fiber cross-sectional area] and a significant increase in the P(sub o)/E(sub o) ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type 1 fiber diameter (by 36%), peak force (by 29%), and V(sub o)(by 48%) but had no significant effect on P(sub o), E(sub o) or P(sub o)/E(sub o). These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type 1 fiber atrophy and to partially restore type 1 peak isometric force and V(sub o) to WB levels. However, the NWB-induced reductions in P(sub o) and E(sub o) which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

Widrick, Jeffrey J.; Bangart, Jill J.; Karhanek, Miloslav; Fitts, Robert H.

1996-01-01

49

Quantitative alterations in the function of bone forming cells due to reduced weight bearing  

NASA Technical Reports Server (NTRS)

Rats subjected to spaceflight or suspended in a non-weight bearing position for 2 to 3 weeks, show a significant reduction in new bone formation. This reduction is associated with a decrease in akaline phosphatase activity in the differentiated osteoblast population. Those cells in the siaphyseal region of bone are more affected than the same cell type in metaphyseal bone. Measurements of alkaline phosphate activity in specific regions of bone, and the autoradiographic localization of H(3) proline in bone forming areas are described. Concomitant with decreased bone matrix synthesis, the osteoblast population also demonstrate changes in the Golgi/lysosomal complex as a result of whole animal suspension. Morphometric techniques are being applied for quantitation of the lysosomal population and the percentage of lysosomal or Golgi bodies containing acid phosphatase activity.

Doty, S. B.

1985-01-01

50

Fixation of chondral fracture of the weight-bearing area of the lateral femoral condyle in an adolescent.  

PubMed

Purely chondral fractures of the distal femur associated with patellar dislocation are uncommon, and treatment varies from fixation to debridement and marrow stimulation techniques. The unusual case reported here involves an adolescent who underwent fixation of a purely chondral fracture involving a large weight-bearing portion of the lateral femoral condyle. Chondral fracture healing was confirmed on follow-up magnetic resonance imaging and arthroscopic examination. This case suggests that fixation of purely chondral fractures can be successful in weight-bearing areas of the knee. Level of evidence V. PMID:24414379

Chan, Chung Ming; King, Joseph J; Farmer, Kevin W

2014-06-01

51

Benign acute childhood myositis--a rare cause of abnormal gait.  

PubMed

Benign acute childhood myositis is a rare postviral myositis seen in school-aged children after a common upper respiratory infection (URI), most commonly caused by influenza [J Microbiol Immunol Infect 2004;37:95-98]. Predominantly seen in boys, this condition causes bilateral calf tenderness and pain with ambulation, often presenting as a refusal to bear weight. To avoid activation within the gastroc-soleus complex, the child will frequently compensate with a “Frankenstein gait,” described as a stiff-legged posture with shuffling gait [CMAJ 2009;181:711-713]. The child may also walk on his toes or refuse to walk at all. This refusal to bear weight can be alarming to both providers and parents, resulting in extensive workups. We present the case of a 5-year-old boy who presented to the emergency department with a chief complaint of leg pain and refusal to walk. Further history revealed a resolved URI approximately 5 days prior. He was noted to have an elevated creatinine kinase with no evidence of renal insufficiency. He had no progression or complications, and his symptoms resolved spontaneously with minimal supportive treatment. Benign acute childhood myositis should be considered within the broad differential that surrounds a limping child or one who refuses to bear weight. Having insight into the condition with its characteristic gait abnormalities and associated URI history can often prevent extensive workups and be treated supportively in the outpatient setting. PMID:24126025

Hall, Gregory; Schranz, Craig I

2014-02-01

52

Non-weight bearing-induced muscle weakness: the role of myosin quantity and quality in MHC type II fibers  

PubMed Central

We tested the hypothesis that non-weight bearing-induced muscle weakness (i.e., specific force) results from decreases in myosin protein quantity (i.e., myosin content per half-sarcomere and the ratio of myosin to actin) and quality (i.e., force per half-sarcomere and population of myosin heads in the strong-binding state during muscle contraction) in single myosin heavy chain (MHC) type II fibers. Fisher-344 rats were assigned to weight-bearing control (Con) or non-weight bearing (NWB). The NWB rats were hindlimb unloaded for 2 wk. Diameter, force, and MHC content were determined in permeabilized single fibers from the semimembranosus muscle. MHC isoform and the ratio of MHC to actin in each fiber were determined by gel electrophoresis and silver staining techniques. The structural distribution of myosin from spin-labeled fiber bundles during maximal isometric contraction was evaluated using electron paramagnetic resonance spectroscopy. Specific force (peak force per cross-sectional area) in MHC type IIB and IIXB fibers from NWB was significantly reduced by 38% and 18%, respectively. MHC content per half-sarcomere was significantly reduced by 21%. Two weeks of hindlimb unloading resulted in a reduced force per half-sarcomere of 52% and fraction of myosin strong-binding during contraction of 34%. The results suggest that reduced myosin and actin content (quantity) and myosin quality concomitantly contribute to non-weight bearing-related muscle weakness.

Kim, Jong-Hee

2014-01-01

53

Thermographic Study in the Diagnosis of Some Injuries and Diseases of the Weight-Bearing Locomotor Apparatus.  

National Technical Information Service (NTIS)

The purpose of this research was the study of the possibility of using thermography to diagnosis some injuries and diseases of the weight-bearing locomotor apparatus. In thermography images are obtained similar in nature of lighting to images on a televis...

A. B. Goldshtein A. G. Vykhovskaya

1971-01-01

54

Effects of early weight bearing on the functional recovery of ambulatory children with cerebral palsy after bilateral proximal femoral osteotomy.  

PubMed

This study evaluates the effects of early versus delayed weight bearing on the functional recovery of ambulatory children with cerebral palsy (CP) after they have undergone proximal femoral osteotomies (PFOs). We retrospectively reviewed the cases of 25 ambulatory children with CP who underwent PFO to correct excessive hip internal rotation and intoeing. Thirteen children were permitted to weight-bear as tolerated (WBAT) immediately after surgery, and 12 were placed on non-weight bearing restrictions for 3 to 7 weeks (mean +/- SD, 30 +/- 6.7 days). There were no major complications. The children in the WBAT group initiated standing 26 days sooner and returned to baseline walking almost 4 months sooner than those on non-weight bearing restrictions. Pain at 8 days postoperatively was significantly less for the WBAT group, but pain at the time of initial standing and walking was not significantly different between groups. In conclusion, early mobilization after PFOs in children with CP is safe, with reduced recovery time, and with decreased pain. PMID:17717468

Schaefer, Megan K; McCarthy, James J; Josephic, Kyle

2007-09-01

55

Non-weight bearing-induced muscle weakness: the role of myosin quantity and quality in MHC type II fibers.  

PubMed

We tested the hypothesis that non-weight bearing-induced muscle weakness (i.e., specific force) results from decreases in myosin protein quantity (i.e., myosin content per half-sarcomere and the ratio of myosin to actin) and quality (i.e., force per half-sarcomere and population of myosin heads in the strong-binding state during muscle contraction) in single myosin heavy chain (MHC) type II fibers. Fisher-344 rats were assigned to weight-bearing control (Con) or non-weight bearing (NWB). The NWB rats were hindlimb unloaded for 2 wk. Diameter, force, and MHC content were determined in permeabilized single fibers from the semimembranosus muscle. MHC isoform and the ratio of MHC to actin in each fiber were determined by gel electrophoresis and silver staining techniques. The structural distribution of myosin from spin-labeled fiber bundles during maximal isometric contraction was evaluated using electron paramagnetic resonance spectroscopy. Specific force (peak force per cross-sectional area) in MHC type IIB and IIXB fibers from NWB was significantly reduced by 38% and 18%, respectively. MHC content per half-sarcomere was significantly reduced by 21%. Two weeks of hindlimb unloading resulted in a reduced force per half-sarcomere of 52% and fraction of myosin strong-binding during contraction of 34%. The results suggest that reduced myosin and actin content (quantity) and myosin quality concomitantly contribute to non-weight bearing-related muscle weakness. PMID:24829495

Kim, Jong-Hee; Thompson, LaDora V

2014-07-15

56

Continuous Passive Motion, Early Weight Bearing, and Active Motion following Knee Articular Cartilage Repair: Evidence for Clinical Practice  

Microsoft Academic Search

Objective: To systematically review the literature regarding postoperative rehabilitation for articular cartilage repair: (1) does the use of continuous passive motion (CPM) enhance healing, and if so, what parameters should be applied? (2) Can active range of motion (AROM) be used in place of or with CPM? (3) When can individuals safely resume weight bearing (WB) following repair? Data Sources:

Jennifer S. Howard; Carl G. Mattacola; Spencer E. Romine; Christian Lattermann

2010-01-01

57

Balance Asymmetry in Parkinson's Disease and Its Contribution to Freezing of Gait  

PubMed Central

Balance control (the ability to maintain an upright posture) is asymmetrically controlled in a proportion of patients with Parkinson’s disease. Gait asymmetries have been linked to the pathophysiology of freezing of gait. We speculate that asymmetries in balance could contribute to freezing by a) hampering the unloading of the stepping leg and/or b) leading to a preferred stance leg during gait, which then results in asymmetric gait. To investigate this, we examined the relationship between balance control and weight-bearing asymmetries and freezing. We included 20 human patients with Parkinson (tested OFF medication; nine freezers) and nine healthy controls. Balance was perturbed in the sagittal plane, using continuous multi-sine perturbations, applied by a motion platform and by a force at the sacrum. Applying closed-loop system identification techniques, relating the body sway angle to the joint torques of each leg separately, determined the relative contribution of each ankle and hip joint to the total amount of joint torque. We also calculated weight-bearing asymmetries. We determined the 99-percent confidence interval of weight-bearing and balance-control asymmetry using the responses of the healthy controls. Freezers did not have larger asymmetries in weight bearing (p?=?0.85) nor more asymmetrical balance control compared to non-freezers (p?=?0.25). The healthy linear one-to-one relationship between weight bearing and balance control was significantly different for freezers and non-freezers (p?=?0.01). Specifically, non-freezers had a significant relationship between weight bearing and balance control (p?=?0.02), whereas this relation was not significant for freezers (p?=?0.15). Balance control is asymmetrical in most patients (about 75 percent) with Parkinson’s disease, but this asymmetry is not related to freezing. The relationship between weight bearing and balance control seems to be less pronounced in freezers, compared to healthy controls and non-freezers. However, this relationship should be investigated further in larger groups of patients.

Boonstra, Tjitske A.; van Vugt, Jeroen P. P.; van der Kooij, Herman; Bloem, Bastiaan R.

2014-01-01

58

Deformations, mechanical strains and stresses across the different hierarchical scales in weight-bearing soft tissues.  

PubMed

Sustained internal tissue loads (deformations, mechanical strains and stresses) which develop during immobile weight-bearing postures such as while in bed or in a chair were identified as a fundamental cause for the onset and progression of pressure ulcers (PUs), particularly of the deep tissue injury (DTI) type. The sustained loading may compromise tissue viability either directly, by geometrically distorting cells, or indirectly, by distorting the vasculature or lymphatic networks or, at the micro-scale, by distorting cellular organelles involved in regulating transport, e.g. the plasma membrane, since transport-control-mechanisms are essential for adequate biological function of cells. In this article we provide a comprehensive, rigorous review of the up-to-date published computational-modeling-work as well as relevant experimental studies concerning tissue deformations, strains and stresses across the different hierarchical scales: tissue-scale [cm], meso-scale [mm] and cell-scale [?m]. Viability of tissues exposed to sustained loading should be investigated in all dimensional scales, from the macro to micro, in order to provide complete understanding of the etiology of PUs and DTIs and in particular, for identifying individuals for whom and conditions at which the susceptibility to these injuries might be greater. Emerging relevant bioengineering methods of computer simulation such as multiscale and multiphysics modeling will undoubtedly contribute to the aetiological research in this field in the near future. PMID:22520396

Shoham, Naama; Gefen, Amit

2012-05-01

59

Gait Style and Gait Content: Bilinear Models for Gait Recognition Using Gait Resampling  

Microsoft Academic Search

Human Identification using gait is a challenging com- puter vision task due to the dynamic motion of gait and the existence of various sources of variations suchas viewpoint, walking surface, clothing, etc. In this paper we propose a gait recognition algorithm based on bilinear decompo- sition of gait data into time-invariant gait-style and time- dependent gait-content factors. We developed a

Chan-su Lee; Ahmed M. Elgammal

2004-01-01

60

Kinematic and dynamic gait compensations resulting from knee instability in a rat model of osteoarthritis  

PubMed Central

Introduction Osteoarthritis (OA) results in pain and disability; however, preclinical OA models often focus on joint-level changes. Gait analysis is one method used to evaluate both preclinical OA models and OA patients. The objective of this study is to describe spatiotemporal and ground reaction force changes in a rat medial meniscus transection (MMT) model of knee OA and to compare these gait measures with assays of weight bearing and tactile allodynia. Methods Sixteen rats were used in the study. The medial collateral ligament (MCL) was transected in twelve Lewis rats (male, 200 to 250 g); in six rats, the medial meniscus was transected, and the remaining six rats served as sham controls. The remaining four rats served as naïve controls. Gait, weight-bearing as measured by an incapacitance meter, and tactile allodynia were assessed on postoperative days 9 to 24. On day 28, knee joints were collected for histology. Cytokine concentrations in the serum were assessed with a 10-plex cytokine panel. Results Weight bearing was not affected by sham or MMT surgery; however, the MMT group had decreased mechanical paw-withdrawal thresholds in the operated limb relative to the contralateral limb (P = 0.017). The gait of the MMT group became increasingly asymmetric from postoperative days 9 to 24 (P = 0.020); moreover, MMT animals tended to spend more time on their contralateral limb than their operated limb while walking (P < 0.1). Ground reaction forces confirmed temporal shifts in symmetry and stance time, as the MMT group had lower vertical and propulsive ground reaction forces in their operated limb relative to the contralateral limb, naïve, and sham controls (P < 0.05). Levels of interleukin 6 in the MMT group tended to be higher than naïve controls (P = 0.072). Histology confirmed increased cartilage damage in the MMT group, consistent with OA initiation. Post hoc analysis revealed that gait symmetry, stance time imbalance, peak propulsive force, and serum interleukin 6 concentrations had significant correlations to the severity of cartilage lesion formation. Conclusion These data indicate significant gait compensations were present in the MMT group relative to medial collateral ligament (MCL) injury (sham) alone and naïve controls. Moreover, these data suggest that gait compensations are likely driven by meniscal instability and/or cartilage damage, and not by MCL injury alone.

2012-01-01

61

Physiological responses and energy cost of walking on the Gait Trainer with and without body weight support in subacute stroke patients  

PubMed Central

Background Robotic-assisted walking after stroke provides intensive task-oriented training. But, despite the growing diffusion of robotic devices little information is available about cardiorespiratory and metabolic responses during electromechanically-assisted repetitive walking exercise. Aim of the study was to determine whether use of an end-effector gait training (GT) machine with body weight support (BWS) would affect physiological responses and energy cost of walking (ECW) in subacute post-stroke hemiplegic patients. Methods Participants: six patients (patient group: PG) with hemiplegia due to stroke (age: 66?±?15y; time since stroke: 8?±?3 weeks; four men) and 6 healthy subjects as control group (CG: age, 76?±?7y; six men). Interventions: overground walking test (OWT) and GT-assisted walking with 0%, 30% and 50% BWS (GT-BWS0%, 30% and 50%). Main Outcome Measures: heart rate (HR), pulmonary ventilation, oxygen consumption, respiratory exchange ratio (RER) and ECW. Results Intervention conditions significantly affected parameter values in steady state (HR: p?=?0.005, V’E: p?=?0.001, V'O2: p?

2014-01-01

62

Hormonal, hypothalamic and striatal responses to reduced body weight gain are attenuated in anorectic rats bearing small tumors.  

PubMed

Lack of compensatory or even reduced food intake is frequently observed in weight-losing cancer patients and contributes to increased morbidity and mortality. Our previous work has shown increased transcription factor expression in the hypothalamus and ventral striatum of anorectic rats bearing small tumors. mRNA expression of molecules known to be involved in pathways regulating appetite in these structures was therefore assessed in this study. Given that pain, pro-inflammatory cytokines and metabolic hormones can modify food intake, spinal cord cellular activation patterns and plasma concentrations of cytokines and hormones were also studied. Morris hepatoma 7777 cells injected subcutaneously in Buffalo rats provoked a 10% lower body weight and 15% reduction in food intake compared to free-feeding tumor-free animals 4 weeks later when the tumor represented 1-2% of body mass. No differences in spinal cord activation patterns or plasma concentration of pro-inflammatory cytokines were observed between groups. However, the changes in plasma ghrelin and leptin concentrations found in food-restricted weight-matched rats in comparison to ad libitum-fed animals did not occur in anorectic tumor-bearing animals. Real-time PCR showed that tumor-bearing rats did not display the increase in hypothalamic agouti-related peptide mRNA observed in food-restricted weight-matched animals. In addition, microarray analysis and real-time PCR revealed increased ventral striatal prostaglandin D synthase expression in food-restricted animals compared to anorectic tumor-bearing rats. These findings indicate that blunted hypothalamic AgRP mRNA expression, probably as a consequence of relatively high leptin and low ghrelin concentrations, and reduced ventral striatal prostaglandin D synthesis play a role in maintaining cancer-associated anorexia. PMID:21334429

Pourtau, Line; Leemburg, Susan; Roux, Pascale; Leste-Lasserre, Thierry; Costaglioli, Patricia; Garbay, Bertrand; Drutel, Guillaume; Konsman, Jan Pieter

2011-05-01

63

Upright, Weight-bearing, Dynamic-kinetic Magnetic Resonance Imaging of the Spine — Review of the First Clinical Results  

Microsoft Academic Search

Magnetic resonance imaging has, until recently, been limited to scans with patients in the recumbent position. However, a new fully open magnetic resonance imaging unit has been configured to allow upright, partially upright, and recumbent imaging, enabling weight-bearing positional evaluation of the spinal column during various dynamic-kinetic manoeuvres for patients with degenerative conditions of the spine. In a prospective non-statistical

JS Dworkin; M Gianni; M Gelbien; RB Wolf; J Damadian

2003-01-01

64

Human Identication Using Gait  

Microsoft Academic Search

Gait refers to the style of walking of an individual. This paper presents a view-invariant approach for human identication at a distance, using gait recognition. Recognition of a person from their gait is a biometric of increasing interest. Based on principal component analysis (PCA), this paper describes a simple, but ecient approach to gait recognition. Binarized silhouettes of a motion

Murat EK

65

Synergistic ablation does not affect atrophy or altered myosin heavy chain expression in the non-weight bearing soleus muscle  

NASA Technical Reports Server (NTRS)

The purpose of this study was to investigate whether the soleus muscle undergoes atrophy and alterations in myosin heavy chain (MHC) composition during non-weight bearing in the absence of synergists. Thirty-two female rats were randomly assigned to four groups: control (C), synergistic ablation (ABL) of the gastrocnemius and plantaris muscles to overload the soleus muscle, hindlimb suspension (HLS), or a combination of synergistic ablation and hindlimb suspension (HLS-ABL). After 28 days of hindlimb suspension, soleus atrophy was more pronounced in HLS (58%) than in HLS-ABL (43%) rats. Compared to C rats, non-weight bearing decreased mixed and myofibrillar protein contents and Type I MHC 49%, 45%, and 7%, respectively, in HLS animals. In addition, de novo expression of fast Type IIx and Type IIb MHC (5% and 2%, respectively) was observed in HLS animals. Similarly, when compared to C rats, mixed and myofibrillar protein contents and Type I MHC decreased 43%, 46%, and 4%, respectively, in HLS-ABL animals. Also, de novo expression of Type IIx (4%) and IIb (1%) MHC was observed. Collectively, these data indicate that the loss of muscle protein and Type I MHC, and the de novo expression of Type IIx and Type IIb MHC in the rat soleus occur independently of the presence of synergists during non-weight bearing. Furthermore, these results confirm the contention that soleus mass and MHC expression are highly sensitive to alterations in mechanical load.

Linderman, J. K.; Talmadge, R. J.; Gosselink, K. L.; Tri, P. N.; Roy, R. R.; Grindeland, R. E.

1996-01-01

66

Factors in high-flex posterior stabilized fixed-bearing total knee arthroplasty affecting in vivo kinematics and anterior tibial post impingement during gait.  

PubMed

One of the most important issues in high-flex posterior stabilized total knee arthroplasty (TKA) is anterior tibial post impingement. We examined 20 knees and 2 TKA designs to evaluate the in vivo kinematics during gait using fluoroscopic image analysis. The AP positions in both stance and swing phases were significantly larger and more anterior in J-curved design TKA compared with Single radius design TKA. Anterior tibial post impingement was observed in five knees implanted with Legacy-flex, and in four of the five knees they were not hyperextended. No impingement was observed with NRG. Less constraint and tibial posterior slope might lead to large AP translations and anterior tibial post impingement. Implant design and operative procedures for high-flexion TKAs affect the in vivo kinematics and the occurrence of anterior tibial post impingement. PMID:23454107

Tamaki, Masashi; Tomita, Tetsuya; Yamazaki, Takaharu; Yoshikawa, Hideki; Sugamoto, Kazuomi

2013-12-01

67

Bone Marrow Lesions and Joint Effusion are Strongly and Independently Associated with Weight-Bearing Pain in Knee Osteoarthritis: Data from the Osteoarthritis Initiative  

PubMed Central

Objective It is widely believed that there are multiple sources of pain at a tissue level in osteoarthritis (OA). MRIs provide a wealth of anatomic information and may allow identification of specific features associated with pain. We hypothesized that in knees with OA, bone marrow lesions (BMLs), synovitis, and effusion would be associated with weight-bearing and (less so with) non-weight-bearing pain independently. Methods In a cross-sectional study of persons with symptomatic knee OA using univariate and multivariate logistic regressions with maximal BML, effusion, and synovitis defined by Boston Leeds Osteoarthritis Knee Score as predictors, and knee pain using weight-bearing and non-weight-bearing Western Ontario and McMaster University OA Index pain questions as the outcome, we tested the association between MRI findings and knee symptoms Results 160 participants, mean age 61 (±9.9), mean BMI 30.3 (±4.7) and 50% female, stronger associations were seen with weight-bearing compared with non-weight-bearing knee pain with adjusted risk ratios (RRs) of weight-bearing knee pain, for increasing maximal BML scores of 1.0 (referent) (maximal BML = 0), 1.2, 1.9, and 2.0 (p for trend = 0.006). For effusion scores, adjusted ORs of knee pain were 1.0, 1.7, 2.0, and 2.6 (p for trend = 0.0004); and for synovitis scores, adjusted ORs were 1.0, 1.4, 1.5, and 1.9 (p for trend = 0.22). Conclusion Cross-sectionally, maximal BML and effusion scores are independently associated with weight-bearing and less so with non-weight-bearing knee pain, supporting the idea that pain in OA is multifactorial. These MRI features should be considered as possible new treatment targets in knee OA.

Lo, GH; McAlindon, TE; Niu, J; Zhang, Y; Beals, C; Dabrowski, C; Hellio Le Graverand, MP; Hunter, DJ

2009-01-01

68

Technological advances in interventions to enhance poststroke gait.  

PubMed

Neurologic rehabilitation interventions may be either therapeutic or compensatory. Included in this article are lower extremity functional electrical stimulation, body weight-supported treadmill training, and lower extremity robotic-assisted gait training. These poststroke gait training therapies are predicated on activity-dependent neuroplasticity. All three interventions have been trialed extensively in research and clinical settings to show a positive effect on various gait parameters and measures of walking performance. This article provides an overview of evidence-based research that supports the efficacy of these three interventions to improve gait, as well as providing perspective on future developments to enhance poststroke gait in neurologic rehabilitation. PMID:23598265

Sheffler, Lynne R; Chae, John

2013-05-01

69

Muscle glucose uptake in the rat after suspension with single hindlimb weight bearing  

NASA Technical Reports Server (NTRS)

An examination is conducted of the effect of nonweight-bearing conditions, and the systemic influences of simulated microgravity on rat hindlimb muscles. The results obtained suggest that the increases in hindlimb muscle glucose uptake and extracellular space associated with simulated microgravity persist with hindlimb weightbearing, despite the prevention of muscle atrophy. The mechanism (or mechanisms) responsible for these effects are currently unknown.

Stump, Craig S.; Woodman, Christopher R.; Fregosi, Ralph F.; Tipton, Charles M.

1993-01-01

70

Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice  

NASA Astrophysics Data System (ADS)

Astronauts on long duration missions continue to experience bone loss, as much as 1–2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12–20 m/min) and daily run time duration (32–51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (?9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that bone formation can be increased even in the presence of reduced weight bearing. These data suggest that moderately vigorous endurance exercise and resistance training, through treadmill running or climb training mitigates decrements in vBMD during 21 days of reduced weight bearing. Consistent with our hypothesis, tower climb training, most pronounced in the tibia mid-diaphysis, provides a more potent osteogenic response compared to treadmill running.

Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

2014-06-01

71

Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings  

Microsoft Academic Search

Summary  The association of long-term sport-specific exercise loading with cross-sectional geometry of the weight-bearing tibia was\\u000a evaluated among 204 female athletes representing five different exercise loadings and 50 referents. All exercises involving\\u000a ground impacts (e.g., endurance running, ball games, jumping) were associated with thicker cortex at the distal and diaphyseal\\u000a sites of the tibia and also with large diaphyseal cross-section, whereas

R. Nikander; P. Kannus; T. Rantalainen; K. Uusi-Rasi; A. Heinonen; H. Sievänen

2010-01-01

72

Gait disorders.  

PubMed

This chapter deals with the neuronal mechanisms underlying impaired gait. The aim is, first, a better understanding of the underlying pathophysiology and, second, the selection of an adequate treatment. One of the first symptoms of a lesion within the central motor system perceived by patients is a movement disorder, which is most characteristic during locomotion, e.g. in patients suffering spasticity after stroke or a spinal cord injury or Parkinson disease. By the recording and analysis of electrophysiological and biomechanical signals during a movement, the significance of impaired reflex behavior or muscle tone and its contribution to the movement disorder can reliably be assessed. Adequate treatment should not be restricted to the correction of an isolated clinical sign but should be based on the mechanisms underlying the movement disorder that impairs the patient. Therapy should be directed toward functional training, which takes advantage of the plasticity of the nervous system. In the future a combination of repair and functional training will further improve the mobility of disabled patients. PMID:23312637

Dietz, V

2013-01-01

73

Human Gait Recognition  

Microsoft Academic Search

The reliable extraction of characteristic gait features from image sequences and their recognition are two important issues in gait recognition. In this paper, we propose a novel 2-step, model-based approach to gait recognition by employing a 5-link biped locomotion human model. We first extract the gait features from image sequences using the Metropolis-Hasting method. Hidden Markov Models are then trained

Rong Zhang; Christian Vogler; Dimitris Metaxas

2004-01-01

74

Gait pattern differences in children with unilateral cerebral palsy.  

PubMed

Children with cerebral palsy (CP) often have atypical body posture patterns and abnormal gait patterns resulting from functional strategies to compensate for primary anomalies that are directly attributable to damage to the central nervous system. Our previous study revealed two different postural patterns in children with unilateral CP: (1) a pattern with overloading of the affected body side and (2) a pattern with under-loading of the affected side. The purpose of present study was to test whether different gait patterns dependent on weight distribution between the affected and unaffected body sides could be detected in these children. The study included 45 outpatients with unilateral CP and 51 children with mild scoliosis (reference group). The examination consisted of two inter-related parts: paedobarographic measurements of the body mass distribution between the body sides and three-dimensional instrumented gait analysis. Using cluster analysis based on the Gillette Gait Index (GGI) values, three gait patterns were described: a scoliotic gait pattern and two hemiplegic gait patterns, corresponding to overloading/under-loading of the hemi-side, which are the pro-gravitational gait pattern (PGP) and the anti-gravitational gait pattern (AGP), respectively. The results of this study showed that subjects with AGP presented a higher degree of deviation from the normal gait than children with PGP. This proof that there are differences in the GGI between the AGP and PGP could be a starting point to identify kinematic differences between these gaits in a follow-up study. PMID:24946266

Szopa, Andrzej; Domagalska-Szopa, Ma?gorzata; Czamara, Andrzej

2014-10-01

75

Control of Gait Initiation  

Microsoft Academic Search

The initiation of gait from a standing posture by 6 subjects, who took controlled-length steps, was analyzed. Using an inverted-pendulum model, we found that the duration of gait initiation was independent of gait velocity. This finding suggests that subjects' biomechanical constants are the determining factors for initiating movement. Both the instantaneous velocity of the center of gravity at the end

Yvon Brenière; Manh Cuong Do

1991-01-01

76

Effect of spaceflight on the non-weight-bearing bones of rat skeleton  

NASA Technical Reports Server (NTRS)

The effects of weightlessness on the integrated growth and remodeling of nonweight-bearing bones (the mandibles, teeth, and ribs) were studied. Rats prelabeled with tetracycline to mark the surfaces of bone and tooth formation were subjected to spaceflight conditions for 18.5 days, followed by further injections of tetracycline on days 6 and 29 postflight.Results show that spaceflight conditions did not alter the rate of periosteal bone formation in the ribs and regions of the mandibles covered by masticatory muscles, although bone formation-calcification rates were found to be impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was found to be significantly reduced. While total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, it was determined that weightless conditions caused a delay in the maturation of bone mineral and matrix in the jaws. These anomalies were found to be corrected by 29 days postflight. These results indicate that most of the nonweight-bearing bones of the rat skeleton are at risk to the effects of weightlessness.

Simmons, D. J.; Russell, J. E.; Winter, F.; Tran Van, P.; Vignery, A.; Baron, R.; Rosenberg, G. D.; Walker, W. V.

1983-01-01

77

A mechanized gait trainer for restoring gait in nonambulatory subjects  

Microsoft Academic Search

Hesse S, Uhlenbrock D, Werner C, Bardeleben A. A mechanized gait trainer for restoring gait in nonambulatory subjects. Arch Phys Med Rehabil 2000;81:1158-61. Objective: To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. Device: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40%

Stefan Hesse; Dietmar Uhlenbrock; Cordula Werner; Anita Bardeleben

2000-01-01

78

Do external stimuli impact the gait of children with idiopathic toe walking? A study protocol for a within-subject randomised control trial  

PubMed Central

Introduction Frequently, toe walking gait is the result of disease processes, trauma or neurogenic influences. Idiopathic toe walking (ITW) is, by definition, the diagnosis of a toe walking gait adopted in the absence of one of these medical conditions. Long-term ITW has been associated with reduced ankle range of motion. Reported treatments have included serial casting, Botulinum toxin type A or surgery to improve the ankle range of motion. Investigating the impact of simple and non-invasive treatment options for ITW is important for future research and clinical outcomes. This study investigates the immediate impact of footwear, footwear with orthotics and whole body vibration on ITW to determine if any one intervention improves heel contact and spatial-temporal gait measures. This determination is important for future clinical trials into treatment effectiveness. Methods and analysis Design: this protocol describes a within-subject randomised controlled trial that measures changes in gait following changes in external stimuli. Participants: 15 children diagnosed with an ITW gait will be recruited from the Victorian Paediatric Rehabilitation Service at Monash Children's Hospital Toe Walking Clinic provided they have ITW and meet the inclusion criteria. Procedure: participants will have their gait recorded walking barefoot, in usual footwear, a custom-made, full-length carbon fibre orthotic in usual footwear and following whole body vibration. Outcome measures will include the presence of bilateral heel contact preintervention and postintervention, stride length (cm), stride width (cm), left and right stride time (s), left and right stance and swing percentage of the gait cycle, gait velocity (m/s), left and right foot toe in/toe out angle (°) and weight-bearing lunge pre and post each condition. Ethics and dissemination The results of this study will be published at the conclusion and have been approved by Southern Health HREC:12102B. Clinical trial registry number ACTRN12612000975897.

Williams, Cylie M; Michalitsis, Joanne; Murphy, Anna; Rawicki, Barry; Haines, Terry P

2013-01-01

79

Gait-related brain activity in people with Parkinson disease with freezing of gait.  

PubMed

Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing--"FoG+" and people who do not experience freezing--"FoG-". Nine FoG+ and nine FoG- imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG- groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG-. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG-. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere. PMID:24595265

Peterson, Daniel S; Pickett, Kristen A; Duncan, Ryan; Perlmutter, Joel; Earhart, Gammon M

2014-01-01

80

Gait-Related Brain Activity in People with Parkinson Disease with Freezing of Gait  

PubMed Central

Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing- “FoG+” and people who do not experience freezing- ”FoG?“. Nine FoG+ and nine FoG? imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG? groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG?. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG?. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere.

Peterson, Daniel S.; Pickett, Kristen A.; Duncan, Ryan; Perlmutter, Joel; Earhart, Gammon M.

2014-01-01

81

Tips of the trade #26. Treatment of amputation residual limb ulcers with a hydroactive dressing and continued weight bearing.  

PubMed

This paper discusses treatment methods for amputation residual limb (stump) ulcers and infected or failed-amputation wounds. Local wound care and abstinence from prosthetic limb use and weight bearing have been found effective in the treatment of decubitus ulcers, as has the use of occlusive hydroactive dressings such as DuoDERM (ConvaTec, Princeton, NJ). DuoDERM application and prosthetic socket modification have been found useful for the treatment of decubitus ulcers in ambulatory patients. The techniques of, and benefits obtained from, DuoDERM therapy are explored; we conclude that the relief of local wound pressure and shear forces obtained with this therapy generally enhances ambulation capacity. PMID:2381738

Pinzur, M S; Osterman, H

1990-07-01

82

A rare case of bilateral non-weight bearing posterior aspect of lateral femoral condyle osteochondral fracture and its management.  

PubMed

Osteochondral fracture of the lateral femoral condyle can be a real challenging injury to diagnose on initial presentation. The authors report a rare case of bilateral involvement of posterior aspect of lateral femoral condyle osteochondral fracture in a young 15-year-old boy. This was managed with excision of these osteochondral fragments, as the site involved was on the posterior non-weight bearing area of the femur along with chronicity of the injury dictating excision as a reasonable choice of management. Good outcome for such injury is based on an early diagnosis and prompt treatment along with an early rehabilitation for such cases. Our patient has an excellent 2?years outcome with a Knee Society score of 95 after undergoing excision of these osteochondral fragments in both knees in succession. PMID:24825555

Shaikh, Aamir Hassan; Stanclik, Jaroslaw; Murphy, Paul G D

2014-01-01

83

Normal and shear forces between surfaces bearing porcine gastric mucin, a high-molecular-weight glycoprotein.  

PubMed

A surface force balance was used to measure the normal and shear forces between two mica surfaces each bearing an adsorbed layer of porcine gastric mucin ("Orthana" mucin), genetically similar to human MUC6. This mucin is a highly purified, 546 kDa, weakly negative, polyampholytic molecule with a "dumbbell" structure. Both bare (HP) and hydrophobized (HB) mica substrates were used, and forces were measured under 1 and 30 mg/mL mucin solutions, under pure (no-added-salt) water, and under 0.1 M aqueous Na(+) solution. Normal surface forces were monotonically repulsive in all cases, with onset of repulsion occurring at smaller surface separations, D, in the 0.1 M salt solutions (? 20 nm, compared with ?40 nm for no added salt). Repulsion on HP mica was greater on surface compression than decompression, an effect, attributed to bridging and slow-relaxing additional adsorption on compression, not seen on HB mica, a difference attributed to the denser coverage of mucin hydrophobic moieties on the HB surface. Friction forces increased with compression in all cases, showing hysteretic behavior on HP but not on HB mica, commensurate with the hysteresis observed in the normal measurements. Low friction coefficients ? (= ?F(s)/?F(n) < 0.05) were seen up to mean pressures

? 0.5 to 1.0 MPa, attributed to low interpenetration of the opposed layers together with hydration lubrication effects, with higher ? (up to 0.4) at higher

attributed to interlayer entanglements and to bridging (for the case of HP mica). Shear forces increased only weakly with sliding speed over the range investigated (80-820 nm s(-1)). The lower friction with HB relative to HP mica suggests a selectivity of the HB surface to the hydrophobic moieties of the mucin that in consequence exposes relatively more of the better-lubricating hydrophilic groups. This surface-selectivity effect on lubrication may have a generality extending to other biological macromolecules that contain both hydrophilic and hydrophobic groups. PMID:21341680

Harvey, Neale M; Yakubov, Gleb E; Stokes, Jason R; Klein, Jacob

2011-04-11

84

Gait Analysis in Rats with Single Joint Inflammation: Influence of Experimental Factors  

PubMed Central

Disability and movement-related pain are major symptoms of joint disease, motivating the development of methods to quantify motor behaviour in rodent joint pain models. We used observational scoring and automated methods to compare weight bearing during locomotion and during standing after single joint inflammation induced by Freund's complete adjuvant (0.12–8.0 mg/mL) or carrageenan (0.47–30 mg/mL). Automated gait analysis was based on video capture of prints generated by light projected into the long edge of the floor of a walkway, producing an illuminated image of the contact area of each paw with light intensity reflecting the contact pressure. Weight bearing was calculated as an area-integrated paw pressure, that is, the light intensity of all pixels activated during the contact phase of a paw placement. Automated static weight bearing was measured with the Incapacitance tester. Pharmacological sensitivity of weight-bearing during locomotion was tested in carrageenan-induced monoarthritis by administration of the commonly used analgesics diclofenac, ibuprofen, and naproxen, as well as oxycodone and paracetamol. Observational scoring and automated quantification yielded similar results. We found that the window between control rats and monoarthritic rats was greater during locomotion. The response was more pronounced for inflammation in the ankle as compared to the knee, suggesting a methodological advantage of using this injection site. The effects of both Freund's complete adjuvant and carrageenan were concentration related, but Freund's incomplete adjuvant was found to be as effective as lower, commonly used concentrations of the complete adjuvant. The results show that gait analysis can be an effective method to quantify behavioural effects of single joint inflammation in the rat, sensitive to analgesic treatment.

Angeby Moller, Kristina; Kinert, Susanne; St?rkson, Rolf; Berge, Odd-Geir

2012-01-01

85

Low-cost evaluation and real-time feedback of static and dynamic weight bearing asymmetry in patients undergoing in-patient physiotherapy rehabilitation for neurological conditions  

PubMed Central

Background Weight bearing asymmetry is common in patients with neurological conditions, and recent advances in gaming technology have produced force platforms that are suitable for use in a clinical setting. The aim of this research is to determine whether commercially-available Wii Balance Boards with customized software providing real-time feedback could be used in a clinical setting to evaluate and improve weight-bearing asymmetry in people with various neurological conditions. Methods Twenty participants (age?=?43.25?±?19.37 years) receiving physiotherapy as a result of a neurological condition performed three trials each of two tasks (static standing and sit-to-stand) with and without visual feedback. Vertical forces were measured using available Wii Balance Boards coupled with customized software that displayed visual feedback in real-time. Primary outcome measures included weight-bearing asymmetry as a percentage of body mass, peak force symmetry index, and a visual analogue scale score rating self-perceived level of asymmetry. Results Weight-bearing asymmetry during the static balance task was significantly reduced (Z?=??2.912, p?=?0.004, ES?=?0.65) with visual feedback. There was no significant difference (Z?=??0.336, p?=?0.737) with visual feedback for the dynamic task, however subgroup analysis indicated that those with higher weight-bearing asymmetry responded the most to feedback. Correlation analysis revealed little or no relationship between participant perception of weight-bearing asymmetry and the results for the static or dynamic balance task (Spearman’s rho: ??=?0.138, p?=?0.561 and ??=?0.018, ? =0.940 respectively). Conclusions These findings suggest that weight-bearing asymmetry can be reduced during static tasks in patients with neurological conditions using inexpensive commercially-available Wii Balance Boards coupled with customized visual feedback software. Further research is needed to determine whether real-time visual feedback is appropriate for reducing dynamic weight-bearing asymmetry, whether improvements result in improved physical function, and how cognitive and physical impairments influence the patient’s ability to respond to treatment.

2013-01-01

86

Effects of different types of weight-bearing loading on bone mass and size in young males: a longitudinal study.  

PubMed

Whether different types of weight bearing loading have different effects on bone mineral accrual in young adults is not well investigated. We measured bone mineral density (BMD, g/cm(2)), bone mineral content (BMC, grams), and bone area (cm(2)) at different sites, in 46 ice hockey players, 18 badminton players and 27 controls, all 17 years of age. A follow up was conducted four years later. The gains in BMD and BMC of the femoral neck and in BMC of the humerus were significantly higher (p<0.05) in badminton players compared with controls during the follow-up time. The badminton players also gained more hip BMC and area compared with the ice hockey players (p<0.05). At the follow-up, the badminton players had higher BMD and BMC at all sites compared with controls (p<0.05). After adjustment for body weight, badminton players had higher hip BMD and BMC, femoral neck BMC, and humeral BMC compared with ice hockey players (p<0.05) at the follow-up. After adjustment for differences in age, there were no differences in BMC or BMD among fathers of badminton players, ice hockey players, or controls, suggesting an absence of selection bias. In conclusion, the novel results of the present study suggest that badminton is associated with higher gains in bone mass and size compared with ice hockey after puberty in men. These differences might be associated with higher strains on the bones from badminton play. PMID:18191629

Nordström, Anna; Högström, Magnus; Nordström, Peter

2008-03-01

87

[Metabolic effects of physical countermeasures against deficient weight-bearing in an experiment with 7-day immersion].  

PubMed

Metabolic effects of physical countermeasures against deficient weight-loading were studied in three groups of 21-30 y.o. volunteers for 7-d dry immersion. Blood serum was investigated for 38 biochemical parameters that characterize myocardium, skeletal musculature, hepatobiliary system, kidney, pancreas, GI tract, prostate, and protein-nucleic, carbohydrate, electrolyte and mineral metabolism. Seven-day DI w/o countermeasures (n = 5) increased concentration of conjugated bilirubin, suppressed activities of muscular (creatine phosphokinase MM) and myocardial enzymes (CPK MB, OBDH), and caused an upward trend in cholesterol, its atherogenic LDP fraction and triglycerides. Mechanic sole stimulation (n = 6) intensified, within the physiological norm, erythrocyte hematolysis raising total bilirubin and potassium. Despite the stimulation, activity of muscle and myocardial enzymes made a decrease. Blood creatinine decreased to a less extent than in the immersed group w/o stimulation, however, lipid parameters did not rise. High-frequency stimulation of the lower leg and hip muscles in the course of immersion (n = 5) was noted to heighten the activity of muscle enzymes and potassium level in blood beyond the physiological norm. Change in creatinine did not reach a statistical significance and lipid metabolism parameters were not different from baseline values. Application of these physical methods of counteracting deficiency of weight bearing did not interfere with redistribution of body liquids due to immersion. Values of the parameters under study were mostly within the normal limits throughout the experimental exposure suggesting absence of pathological developments during DI or in consequence of physical stimulation. Therefore, the reactions were obviously of normal adaptive character. PMID:21970040

Markin, A A; Zhuravleva, O A; Morukov, B V; Zabolotskaia, I V; Vostrikova, L V; Kuzichkin, D S

2011-01-01

88

A palmar pressure sensor for measurement of upper limb weight bearing by the hands during transfers by paraplegics.  

PubMed

Paraplegic patients have to effect transfer from one seat to another by using their upper limbs. In this process the hands bear almost the entire weight of the body in at least some phases of the transfer. It is desirable to train patients, especially those who are elderly and otherwise weak, to distribute their weight so as to avoid large forces being sustained on any one hand for an extended period. It is also desirable to evaluate the effectiveness of assistive devices like lower limb FES in sharing the load on the hand. This study presents a simple and versatile method of measuring palmar hand force during transfers by paraplegic patients. It is important that this force sensor should not interfere with the grasping and stabilizing properties of the hands and should permit normal transferring. The force sensor comprises an air-filled pouch or pillow that can be placed on any surface. This pneumatic sensor feels like upholstery padding on the surface on which it is placed. The sensor integrates the total pressure applied to the surface of the pouch, thereby obtaining the total force exerted by the palm/hand. The fabrication of the sensor is described, as well as the associated measurement circuit. The static calibration shows that the sensor is linear up to 350?N and the dynamic calibration shows that it has a bandwidth of 13?Hz. The sensor was fabricated using an inflated inelastic airbag attached to a pressure transducer. An automatic offset correction circuit in the preamplifier module ensures that any offset due to initial pressure or sensor drift is removed and the output is zero under no load condition. The key to this sensor arrangement is the ease of fitting it into the intended location without disturbing the existing arrangement for the subject's activities of daily living (ADL). PMID:23964668

Kunju, Nissan; Ojha, Rajdeep; Devasahayam, Suresh R

2013-10-01

89

Factors predicting weight-bearing asymmetry 1 month after unilateral total knee arthroplasty: a cross-sectional study  

PubMed Central

Factors predicting weight-bearing asymmetry (WBA) after unilateral total knee arthroplasty (TKA) are not known. However, identifying modifiable and non-modifiable predictors of WBA is needed to optimize rehabilitation, especially since WBA is negatively correlated to poor functional performance. The purpose of this study was to identify factors predictive of WBA during sit-stand transitions for people 1 month following unilateral TKA. Methods Fifty-nine people were tested preoperatively and 1 month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit to Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations. Results WBA, measured as the ratio of surgical/non-surgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD)) 1 month after TKA. Regression analysis identified preoperative WBA (? = 0.40), quadriceps strength ratio (? = 0.31), and hamstrings strength ratio (? = 0.19) as factors predictive of WBA 1 month after TKA (R2 = 0.30). Conclusion Greater amounts of WBA 1 month after TKA are predicted by modifiable factors including habitual movement pattern and asymmetry in quadriceps and hamstrings strength.

Christiansen, Cory L; Bade, Michael J.; Weitzenkamp, David A.; Stevens-Lapsley, Jennifer E.

2012-01-01

90

[Serious foot injury: consider partial amputation designed to preserve leg-length and a weight-bearing stump].  

PubMed

Three patients with physically demanding jobs, a 25-year-old farmer, a 22-year-old market trader and a 32-year-old house painter, each suffered a traumatic injury of one foot. All three underwent amputation in which part of their foot was salvaged and were able to return to their physically demanding jobs. The first patient underwent a Syme's amputation, the second a Pirogoff's amputation and the third a Chopart's amputation. A partial amputation of the foot has several advantages: patients are able to walk without walking aids, particularly in and around the house, due to the presence of a direct weight-bearing stump. With a prosthesis patients may be able to resume their physically demanding jobs, there are fewer problems of functional restraint of the knee and phantom pain is rare. Although these amputations can be technically demanding, an amputation at this level in young as well as older patients with an adequate blood supply to the hind foot is worthwhile and to be recommended for several reasons. PMID:17469316

Zinger, W; Holtslag, H R; Verleisdonk, E J M M

2007-04-01

91

Multiple ligament knee reconstruction clinical follow-up and gait analysis.  

PubMed

Multiple ligament knee injuries are serious and rare injures that have not been studied using advanced gait analysis techniques. The purpose of this study was to perform clinical follow-up and gait analysis on patients with multiple knee ligament reconstruction. Twenty-four patients who underwent a multi-ligament knee reconstruction by a single surgeon volunteered to participate in this study. We performed complete clinical exam including instrumented ACL exam (KT-1000), and radiological exam including weight-bearing and PCL stress radiographs (TELOS) at minimum 2 years post index surgery. In addition, we performed complete three-dimensional gait analysis on 18 patients. We used a 10-camera, high speed (120 Hz) motion analysis system in conjunction with a multi-axis strain-gage force plate which calculated knee joint kinetics and kinematics while subjects performed flat-ground walking and stair-descent tasks. Kinematic and kinetic variables were compared between reconstructed and contralateral knees and unmatched, healthy control knees. All knee joint moments were normalized to subjects' weight. Clinical: Average knee joint flexion/extension 123.6 +/- 15.5/1.7 +/- 3.5, respectively. Average KT-1000 side-to-side difference was 1.2 +/- 2.0 mm, TELOS side-to-side difference on stress radiographs was 4.0 +/- 3.1 mm. Median IKDC score was 67 (range 13-94). Fifty-three percent of patients exhibited radiographic evidence of osteoarthritis (OA) on the operative side; one patient on the contralateral knee. During gait analysis, patients exhibited significantly reduced total knee joint range of motion, and external knee flexion moment in the reconstructed knee compared to the contralateral knee and healthy control knees. The magnitude of these differences was greater while descending a step. Finally, patients who had radiographic evidence of knee joint OA had significantly lower magnitude external knee flexion moment compared to those who did not have OA at the time of follow-up. Greater than 2 years after reconstruction, patients with multi-ligament knee injuries are able to return to daily activities. Gait analysis data suggests that patients may be experiencing higher magnitude changes in sagittal plane kinematics and kinetics during demanding functional tasks (stair decent). Changes in walking gait biomechanics may help explain why this group is experiencing unilateral knee joint degeneration. PMID:19107463

Hart, Joseph M; Blanchard, Berkeley F; Hart, Jennifer A; Montgomery, Scott C; Schoderbek, Robert; Miller, Mark D

2009-03-01

92

A simplified version of the weight-bearing ankle lunge test: Description and test-retest reliability.  

PubMed

The purpose of this study was twofold: (1) to describe a new version of the weight-bearing ankle lunge test (WBLT) that is simple to administer, that allows clinicians and sports medicine practitioners to directly assess (in degrees) the ankle dorsiflexion range of motion in a very short period of time while adopting a comfortable testing position; as well as (2) to determine the test-retest reliability of the ankle dorsiflexion range of motion measure obtained from the new version of the WBLT. A total of 50 active adults completed this study. All participants performed the new version of the WBLT on three different occasions, with a two-week interval between testing sessions. Reliability was examined through the change in the mean between consecutive pairs of testing sessions (ChM), standard error of measurement (SEM), minimal detectable change at 95% confidence interval (MDC95), and intraclass correlation coefficient (ICC2,k). The findings showed negligible or trivial ChM values for all the flexibility measures analysed (<1°). Furthermore, the SEM and MDC95 scores for the ankle dorsiflexion measure were 1.3 and 3.8 respectively, and the ICC2k was 0.95. Therefore, this study demonstrated that the ankle dorsiflexion measure obtained from the new version of the WBLT has excellent test-retest reliability scores. Thus, an observed change larger than 3.8° from baseline scores after performing a treatment would indicate that a real change in ankle dorsiflexion range of motion was likely. PMID:24746162

Cejudo, Antonio; Sainz de Baranda, Pilar; Ayala, Francisco; Santonja, Fernando

2014-08-01

93

Repair of articular cartilage defect in non-weight bearing areas using adipose derived stem cells loaded polyglycolic acid mesh.  

PubMed

The current study was designed to observe chondrogenic differentiation of adipose derived stem cells (ASCs) on fibrous polyglycolic acid (PGA) scaffold stabilized with polylactic acid (PLA), and to further explore the feasibility of using the resulting cell/scaffold constructs to repair full thickness articular cartilage defects in non-weight bearing area in porcine model within a follow-up of 6 months. Autologous ASCs isolated from subcutaneous fat were expanded and seeded on the scaffold to fabricate ASCs/PGA constructs. Chondrogenic differentiation of ASCs in the constructs under chondrogenic induction was monitored with time by measuring the expression of collagen type II (COL II) and glycosaminoglycan (GAG). The constructs after being in vitro induced for 2 weeks were implanted to repair full thickness articular cartilage defects (8mm in diameter, deep to subchondral bone) in femur trochlea (the experimental group), while scaffold alone was implanted to serve as the control. Histologically, the generated neo-cartilage integrated well with its surrounding normal cartilage and subchondral bone in the defects of experimental group at 3 months post-implantation, whereas only fibrous tissue was filled in the defects of control group. Immunohistochemical and toluidine blue staining confirmed the similar distribution of COL II and GAG in the regenerated cartilage as the normal one. A vivid remolding process with post-operation time was also witnessed in the neo-cartilage as its compressive moduli increased significantly from 50.55% of the normal cartilage at 3 months to 88.05% at 6 months. The successful repair thus substantiates the potentiality of using chondrogenic induced ASCs and PGA/PLA scaffold for cartilage regeneration. PMID:19217157

Cui, Lei; Wu, Yaohao; Cen, Lian; Zhou, Heng; Yin, Shuo; Liu, Guangpeng; Liu, Wei; Cao, Yilin

2009-05-01

94

Technological Advances in Interventions to Enhance Post-Stroke Gait  

PubMed Central

Synopsis This article provides a comprehensive review of specific rehabilitation interventions used to enhance hemiparetic gait following stroke. Neurologic rehabilitation interventions may be either therapeutic resulting in enhanced motor recovery or compensatory whereby assistance or substitution for neurological deficits results in improved functional performance. Included in this review are lower extremity functional electrical stimulation (FES), body-weight supported treadmill training (BWSTT), and lower extremity robotic-assisted gait training. These post-stroke gait training therapies are predicated on activity-dependent neuroplasticity which is the concept that cortical reorganization following central nervous system injury may be induced by repetitive, skilled, and cognitively engaging active movement. All three interventions have been trialed extensively in both research and clinical settings to demonstrate a positive effect on various gait parameters and measures of walking performance. However, more evidence is necessary to determine if specific technology-enhanced gait training methods are superior to conventional gait training methods. This review provides an overview of evidence-based research which supports the efficacy of these three interventions to improve gait, as well as provide perspective on future developments to enhance post-stroke gait in neurologic rehabilitation.

Sheffler, Lynne R.; Chae, John

2012-01-01

95

View Invariant Gait Recognition  

Microsoft Academic Search

Recognition by gait is of particular interest since it is the biometric that is available at the lowest resolution, or when\\u000a other biometrics are (intentionally) obscured. Gait as a biometric has now shown increasing recognition capability. There\\u000a are many approaches and these show that recognition can achieve excellent performance on current large databases. The majority\\u000a of these approaches are planar

Richard D. Seely; Michela Goffredo; John N. Carter; Mark S. Nixon

96

A Robot and Control Algorithm That Can Synchronously Assist in Naturalistic Motion During Body-Weight-Supported Gait Training Following Neurologic Injury  

Microsoft Academic Search

Locomotor training using body weight support on a treadmill and manual assistance is a promising rehabilitation technique following neurological injuries, such as spinal cord injury (SCI) and stroke. Previous robots that automate this technique impose constraints on naturalistic walking due to their kinematic structure, and are typically operated in a stiff mode, limiting the ability of the patient or human

Daisuke Aoyagi; Wade E. Ichinose; Susan J. Harkema; David J. Reinkensmeyer; James E. Bobrow

2007-01-01

97

View Invariant Gait Recognition  

NASA Astrophysics Data System (ADS)

Recognition by gait is of particular interest since it is the biometric that is available at the lowest resolution, or when other biometrics are (intentionally) obscured. Gait as a biometric has now shown increasing recognition capability. There are many approaches and these show that recognition can achieve excellent performance on current large databases. The majority of these approaches are planar 2D, largely since the early large databases featured subjects walking in a plane normal to the camera view. To extend deployment capability, we need viewpoint invariant gait biometrics. We describe approaches where viewpoint invariance is achieved by 3D approaches or in 2D. In the first group, the identification relies on parameters extracted from the 3D body deformation during walking. These methods use several video cameras and the 3D reconstruction is achieved after a camera calibration process. On the other hand, the 2D gait biometric approaches use a single camera, usually positioned perpendicular to the subject’s walking direction. Because in real surveillance scenarios a system that operates in an unconstrained environment is necessary, many of the recent gait analysis approaches are orientated toward view-invariant gait recognition.

Seely, Richard D.; Goffredo, Michela; Carter, John N.; Nixon, Mark S.

98

Comparison of Upright Gait with Supine Bungee-Cord Gait  

NASA Technical Reports Server (NTRS)

Running on a treadmill with bungee-cord resistance is currently used on the Russian space station MIR as a countermeasure for the loss of bone and muscular strength which occurs during spaceflight. However, it is unknown whether ground reaction force (GRF) at the feet using bungee-cord resistance is similar to that which occurs during upright walking and running on Earth. We hypothesized-that the DRAMs generated during upright walking and running are greater than the DRAMs generated during supine bungee-cord gait. Eleven healthy subjects walked (4.8 +/- 0.13 km/h, mean +/- SE) and ran (9.1 +/- 0.51 km/h) during upright and supine bungee-cord exercise on an active treadmill. Subjects exercised for 3 min in each condition using a resistance of 1 body weight calibrated during an initial, stationary standing position. Data were sampled at a frequency of 500Hz and the mean of 3 trials was analyzed for each condition. A repeated measures analysis of variance tested significance between the conditions. Peak DRAMs during upright walking were significantly greater (1084.9 +/- 111.4 N) than during supine bungee-cord walking (770.3 +/- 59.8 N; p less than 0.05). Peak GRFs were also significantly greater for upright running (1548.3 +/- 135.4 N) than for supine bungee-cord running (1099.5 +/- 158.46 N). Analysis of GRF curves indicated that forces decreased throughout the stance phase for bungee-cord gait but not during upright gait. These results indicate that bungee-cord exercise may not create sufficient loads at the feet to counteract the loss of bone and muscular strength that occurs during long-duration exposure to microgravity.

Boda, Wanda L.; Hargens, Alan R.; Campbell, J. A.; Yang, C.; Holton, Emily M. (Technical Monitor)

1998-01-01

99

Partial versus unrestricted weight bearing after an uncemented femoral stem in total hip arthroplasty: recommendation of a concise rehabilitation protocol from a systematic review of the literature  

Microsoft Academic Search

The aim of this systematic review was to find evidence-based support in the literature to allow immediate unrestricted weight\\u000a bearing after primary uncemented total hip arthroplasty (THA). Accelerated rehabilitation programs for THA are becoming increasingly\\u000a popular to shorten hospital stay and to facilitate rapid restoration of function. The goals of these rehabilitation programs\\u000a could be more easily achieved if immediate

A. M. Hol; S. van Grinsven; C. Lucas; J. L. C. van Susante; C. J. M. van Loon

2010-01-01

100

In Vivo Motion of Femoral Condyles During Weight-Bearing Flexion After Anterior Cruciate Ligament Rupture Using Biplane Radiography  

PubMed Central

The purpose of this study was to investigate in vivo three- dimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial- lateral and proximal-distal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°. Key Points Three-dimensional tibiofemoral kinematics and femoral condylar motion in ACL-deficient knees during upright weight-bearing flexion were measured using biplane radiography with the geometric center axis. ACL deficiency caused posterior subluxation of the lateral condyle with excess external femoral rotation at early flexion positions. On flexion from 15° to 60°, the lateral condyle moved slightly posteriorly in ACL deficiency leading to reduced extent of external femoral rotation.

Chen, Kaining; Yin, Li; Cheng, Liangjun; Li, Chuan; Chen, Cheng; Yang, Liu

2013-01-01

101

An in vivo study of hindfoot 3D kinetics in stage II posterior tibial tendon dysfunction (PTTD) flatfoot based on weight-bearing CT scan  

PubMed Central

Objective The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing. Methods CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint. Results From non- to full-body-weight-bearing condition, the difference in the talus position relative to the calcaneus in the talocalcaneal joint was 0.6° more dorsiflexed (p = 0.032), 1.4° more everted (p = 0.026), 0.9 mm more anterior (p = 0.031) and 1.0 mm more proximal (p = 0.004) in stage II PTTD flatfoot compared with that in a healthy foot. The navicular position difference relative to the talus in the talonavicular joint was 3° more everted (p = 0.012), 1.3 mm more lateral (p = 0.024), 0.8 mm more anterior (p = 0.037) and 2.1 mm more proximal (p = 0.017). The cuboid position difference relative to the calcaneus in the calcaneocuboid joint did not change significantly in rotation and translation (all p ? 0.08). Conclusion Referring to a previous study regarding both the cadaveric foot and the live foot, joint instability occurred in the hindfoot in simulated weight-bearing condition in patients with stage II PTTD flatfoot. The method used in this study might be applied to clinical analysis of the aetiology and evolution of PTTD flatfoot, and may inform biomechanical analyses of the effects of foot surgery in the future. Cite this article: Bone Joint Res 2013;2:255–63.

Zhang, Y.; Xu, J.; Wang, X.; Huang, J.; Zhang, C.; Chen, L.; Wang, C.; Ma, X.

2013-01-01

102

Gait Analysis in a Rat Model of Osteoarthrosis  

Microsoft Academic Search

Gait analysis has been undertaken in a rat model of osteoarthrosis, induced by intra-articular injection of sodium iodoacetate into the left knee. Two weeks after injection, no disturbances were recorded to the velocity of locomotion, the stride length nor the stride, stance, or swing times. However, clear and consistent reductions in the peak vertical load bearing (Pz) by the affected

K. A Clarke; S. A Heitmeyer; A. G Smith; Y. O Taiwo

1997-01-01

103

Magnetic Bearing  

NASA Technical Reports Server (NTRS)

AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

1996-01-01

104

Gait Analysis for Human Identification  

Microsoft Academic Search

Human gait is an attractive modality for recognizing people at a dis- tance. In this paper we adopt an appearance-based approach to the problem of gait recognition. The width of the outer contour of the binarized silhouette of a walking person is chosen as the basic image feature. Different gait features are extracted from the width vector such as the

Amit A. Kale; Naresh P. Cuntoor; B. Yegnanarayana; A. N. Rajagopalan; Rama Chellappa

2003-01-01

105

Context based gait recognition  

NASA Astrophysics Data System (ADS)

Gait recognition has recently become a popular topic in the field of biometrics. However, the main hurdle is the insufficient recognition rate in the presence of low quality samples. The main focus of this paper is to investigate how the performance of a gait recognition system can be improved using additional information about behavioral patterns of users and the context in which samples have been taken. The obtained results show combining the context information with biometric data improves the performance of the system at a very low cost. The amount of improvement depends on the distinctiveness of the behavioral patterns and the quality of the gait samples. Using the appropriate distinctive behavioral models it is possible to achieve a 100% recognition rate.

Bazazian, Shermin; Gavrilova, Marina

2012-05-01

106

Pelvic control and over-ground walking methodology for impaired gait recovery  

Microsoft Academic Search

In this paper, a methodology for gait rehabilitation, combines over-ground walking, body weight support, pelvic control, and gait assistance are introduced and the integrated platform has been developed. This paper also discusses the gap of state-of-the-art research in gait rehabilitation. Systems like Lokomat and Kineassist were studied and discussed. Initial testing and EMG experiments have been carried out on the

H. B. Lim; K. H. Hoon; K. H. Low; Y. C. Soh; A. Tow

2009-01-01

107

The analysis on period doubling gait and chaotic gait of the compass-gait biped model  

Microsoft Academic Search

The passive dynamic walking model, which can only depend on the gravity and its own inertia, presents stable, high-efficient, natural periodic gait on a slight slope. The stable periodic gait of the robot has a delicate balance of energy conversion, which makes the gait adjust itself as the parameters of the model change. In our work, the cell mapping method

Jie Zhao; Xiaoguang Wu; Xizhe Zang; Yanhe Zhu; Lei Zhu

2011-01-01

108

Low-resolution gait recognition.  

PubMed

Unlike other biometric authentication methods, gait recognition is noninvasive and effective from a distance. However, the performance of gait recognition will suffer in the low-resolution (LR) case. Furthermore, when gait sequences are projected onto a nonoptimal low-dimensional subspace to reduce the data complexity, the performance of gait recognition will also decline. To deal with these two issues, we propose a new algorithm called superresolution with manifold sampling and backprojection (SRMS), which learns the high-resolution (HR) counterparts of LR test images from a collection of HR/LR training gait image patch pairs. Then, we incorporate SRMS into a new algorithm called multilinear tensor-based learning without tuning parameters (MTP) for LR gait recognition. Our contributions include the following: 1) With manifold sampling, the redundancy of gait image patches is remarkably decreased; thus, the superresolution procedure is more efficient and reasonable. 2) Backprojection guarantees that the learned HR gait images and the corresponding LR gait images can be more consistent. 3) The optimal subspace dimension for dimension reduction is automatically determined without introducing extra parameters. 4) Theoretical analysis of the algorithm shows that MTP converges. Experiments on the USF human gait database and the CASIA gait database show the increased efficiency of the proposed algorithm, compared with previous algorithms. PMID:20199936

Zhang, Junping; Pu, Jian; Chen, Changyou; Fleischer, Rudolf

2010-08-01

109

The effect of frog pressure and downward vertical load on hoof wall weight-bearing and third phalanx displacement in the horse--an in vitro study.  

PubMed

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismembered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2,500 N at a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 N load. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frogpressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe. PMID:12219918

Olivier, A; Wannenburg, J; Gottschalk, R D; van der Linde, M J; Groeneveld, H T

2001-12-01

110

Gait or Walking Problems  

MedlinePLUS

... to perform tests that measure muscle strength, fatigue levels, range of motion, spasticity, and balance. some Pts use video cameras to record their observations. computerized devices such as a matt or a platform with sensors can also be used to quantify gait and ...

111

Strength Asymmetry Increases Gait Asymmetry and Variability in Older Women  

PubMed Central

Purpose The aim of the research was to determine how knee extensor strength asymmetry influences gait asymmetry and variability since these gait parameters have been related to mobility and falls in older adults. Methods Strength of the knee extensors was measured in 24 older women (65 – 80 yr). Subjects were separated into symmetrical strength (SS, n = 13) and asymmetrical strength (SA, n = 11) groups using an asymmetry cutoff of 20%. Subjects walked at a standard speed of 0.8 m s?1 and at maximal speed on an instrumented treadmill while kinetic and spatiotemporal gait variables were measured. Gait and strength asymmetry were calculated as the percent difference between legs and gait variability as the coefficient of variation over twenty sequential steps. Results SA had greater strength asymmetry (27.4 ± 5.5%) than SS (11.7 ± 5.4%, P < 0.001). Averaged across speeds, SA had greater single (7.1% vs. 2.5%) and double-limb support time asymmetry (7.0 vs. 4.3%) than SS and greater single-limb support time variability (9.7% vs. 6.6%, all P < 0.05). Group × speed interactions occurred for weight acceptance force variability (P = 0.02) and weight acceptance force asymmetry (P = 0.017) with greater variability at the maximal speed in SA (5.0 ± 2.4% vs. 3.7 ± 1.2%) and greater asymmetry at the maximal speed in SA (6.4 ± 5.3% vs. 2.5 ± 2.3%). Conclusion Gait variability and asymmetry are greater in older women with strength asymmetry and increase when they walk near their maximal capacities. The maintenance of strength symmetry, or development of symmetry through unilateral exercise, may be beneficial in reducing gait asymmetry, gait variability, and fall risk in older adults.

LaRoche, Dain P.; Cook, Summer B.; Mackala, Krzysztof

2012-01-01

112

Gait energy volumes and frontal gait recognition using depth images  

Microsoft Academic Search

Gait energy images (GEIs) and its variants form the basis of many recent appearance-based gait recognition systems. The GEI combines good recognition performance with a simple implementation, though it suffers problems inherent to appearance-based approaches, such as being highly view dependent. In this paper, we extend the concept of the GEI to 3D, to create what we call the gait

Sabesan Sivapalan; Daniel Chen; Simon Denman; Sridha Sridharan; Clinton Fookes

2011-01-01

113

Toward Improved Clinical Relevance of Cartilage Insult Models in the Rabbit Knee: Surgical Access to the Habitual Weight-Bearing Region  

PubMed Central

Objective This article addresses considerations for using a posterior (popliteal) instead of anterior (para-patellar) approach for experimental insult to the rabbit knee medial femoral condyle (MFC) surface in vivo. The posterior approach is particularly advantageous when intending to address the pathomechanisms of OA associated with habitual cartilage loading, or the efficacy of a cartilage repair method, in a clinically relevant experimental setting. Design Studies using anterior versus posterior approaches for such purposes in survival rabbit models of the MFC articular surface insults were systematically surveyed. The anterior-posterior span of the primary weight-bearing region of that surface was demonstrated cadaverically. Results Of a total of 31 papers identified in 2007-2012, an anterior approach was utilized in 28 studies (> 90%). More than half (17/28) explicitly regarded the cranial half (inferior aspect) of the MFC surface as being a “weight-bearing” region. The insult site through anterior approach (identified in figures) was located in the cranial half region in all cases. Cadaverically, however, the center of habitual tibio-femoral contact locations on the MFC surface was located in the caudal half region (posterior aspect) of the MFC surface. The majority of the habitual contact region was accessible only by a posterior surgical approach. Conclusion For the above-noted purposes, use of a posterior (popliteal) approach, rather than an anterior approach, is highly recommended.

Tochigi, Yuki; Buckwalter, Joseph A.; Brown, Thomas D.

2013-01-01

114

In vivo regulation of the beta-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats  

NASA Technical Reports Server (NTRS)

In the weight-bearing hindlimb soleus muscle of the rat, approximately 90% of muscle fibers express the beta-myosin heavy chain (beta-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from beta toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the beta-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length beta-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest beta-promoter fragment (-3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the -3500-, -914-, and -408-bp promoter constructs were significantly reduced ( approximately 40%), compared with the control muscles. However, using the -215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the -408 and -215 bp of the promoter.

Giger, J. M.; Haddad, F.; Qin, A. X.; Baldwin, K. M.

2000-01-01

115

An approach to gait recognition  

Microsoft Academic Search

Human gait is a spatio-temporal phenomenon and typifies the motion characteristics of an individual. The gait of a person is easily recognizable when extracted from a sideview of the person. Accordingly, gait-recognition algorithms work best when presented with images where the person walks parallel to the camera (i.e. the image plane).A set of stances or key frames that occur during

C. Nandini; C. N. RaviKumar

2008-01-01

116

Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees  

NASA Astrophysics Data System (ADS)

We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

Choi, Jang-Hwan; Maier, Andreas; Berger, Martin; Fahrig, Rebecca

2014-03-01

117

Natural Gaits of the Non-Pathological Flat Foot and High-Arched Foot  

PubMed Central

There has been a controversy as to whether or not the non-pathological flat foot and high-arched foot have an effect on human walking activities. The 3D foot scanning system was employed to obtain static footprints from subjects adopting a half-weight-bearing stance. Based upon their footprints, the subjects were divided into two groups: the flat-footed and the high-arched. The plantar pressure measurement system was used to measure and record the subjects' successive natural gaits. Two indices were proposed: distribution of vertical ground reaction force (VGRF) of plantar and the rate of change of footprint areas. Using these two indices to compare the natural gaits of the two subject groups, we found that (1) in stance phase, there is a significant difference (p<0.01) in the distributions of VGRF of plantar; (2) in a stride cycle, there is also a significant difference (p<0.01) in the rate of change of footprint area. Our analysis suggests that when walking, the VGRF of the plantar brings greater muscle tension to the flat-footed while a smaller rate of change of footprint area brings greater stability to the high-arched.

Fan, Yifang; Fan, Yubo; Li, Zhiyu; Lv, Changsheng; Luo, Donglin

2011-01-01

118

Growth hormone, IGF-I, and exercise effects on non-weight-bearing fast muscles of hypophysectomized rats  

NASA Technical Reports Server (NTRS)

The effects of growth hormone (GH) or insulin-like growth factor I (IGF-I) with or without exercise (ladder climbing) in countering the effects of unweighting on fast muscles of hypophysectomized rats during 10 days of hindlimb suspension were determined. Compared with untreated suspended rats, muscle weights were 16-29% larger in GH-treated and 5-15% larger in IGF-I-treated suspended rats. Exercise alone had no effect on muscle weights. Compared with ambulatory control, the medial gastrocnemius weight in suspended, exercised rats was larger after GH treatment and maintained with IGF-I treatment. The combination of GH or IGF-I plus exercise in suspended rats resulted in an increase in size of each predominant fiber type, i.e., types I, I + IIa and IIa + IIx, in the medial gastrocnemius compared with untreated suspended rats. Normal ambulation or exercise during suspension increased the proportion of fibers expressing embryonic myosin heavy chain in hypophysectomized rats. The phenotype of the medial gastrocnemius was minimally affected by GH, IGF-I, and/or exercise. These results show that there is an IGF-I, as well as a GH, and exercise interactive effect in maintaining medial gastrocnemius fiber size in suspended hypophysectomized rats.

Grossman, E. J.; Grindeland, R. E.; Roy, R. R.; Talmadge, R. J.; Evans, J.; Edgerton, V. R.

1997-01-01

119

Short-term effects of self-mobilization with a strap on pain and range of motion of the wrist joint in patients with dorsal wrist pain when weight bearing through the hand: a case series.  

PubMed

Dorsal wrist pain frequently occurs in weight bearing through the hand in patients with distal radius stress injuries, scaphoid impaction syndrome, and dorsal impingement. To improve the wrist extension motion, joint mobilization has been used. However, there is no report on the effects of mobilization on the range of motion (ROM) and pain onset in patients with dorsal wrist pain when weight bearing through the hand. This study determined the effects of self-mobilization with a strap (SMWS) while weight bearing through the hand on the ROM and force generated at the onset of pain (FGOP) and intensity in the wrist joints of patients with dorsal wrist pain. Fifteen patients (six men, nine women) with dorsal wrist pain during weight bearing through the hand were recruited from a workplace-based work-conditioning center. SMWS was applied during five visits for a 1-week period. Both passive and active wrist extension ROM, FGOP, and pain intensity (PI) while pushing down through the hand were measured before and after SMWS. Passive and active ROM of wrist extension and FGOP increased significantly after the five sessions over 1 week of SMWS (p < 0.05). PI decreased significantly after the five sessions of SMWS (p < 0.05). These results suggest that SMWS can be used to increase wrist extension ROM and decrease wrist pain in patients with dorsal wrist pain during weight bearing through the hand. PMID:23830868

Choung, Sung-Dae; Kwon, Oh-Yun; Park, Kyue-Nam; Kim, Si-Hyun; Cynn, Heon-Seock

2013-12-01

120

Gait Recognition and Walking Exercise Intensity Estimation  

PubMed Central

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study.

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-01-01

121

Gait recognition and walking exercise intensity estimation.  

PubMed

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients' exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients' attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-04-01

122

Biofeedback for robotic gait rehabilitation  

Microsoft Academic Search

BACKGROUND: Development and increasing acceptance of rehabilitation robots as well as advances in technology allow new forms of therapy for patients with neurological disorders. Robot-assisted gait therapy can increase the training duration and the intensity for the patients while reducing the physical strain for the therapist. Optimal training effects during gait therapy generally depend on appropriate feedback about performance. Compared

Lars Lünenburger; Gery Colombo; Robert Riener

2007-01-01

123

Gait analysis in forensic medicine  

Microsoft Academic Search

We have combined the basic human ability to recognize other individuals with functional anatomical and biomechanical knowledge, in order to analyze the gait of perpetrators as recorded on surveillance video. The perpetrators are then compared with similar analyses of suspects. At present we give a statement to the police as to whether the perpetrator has a characteristic gait pattern compared

Peter K. Larsen; Erik B. Simonsen; Niels Lynnerup

2007-01-01

124

Gait Analysis and the Bootstrap  

Microsoft Academic Search

This paper is about random coefficient trigonometric regression models and their use in gait analysis. Here gait analysis means free-speed walking on a level surface. Our study focuses on bootstrap-based prediction regions for the angular rotation curves of test children, when the relevant training data are gathered from normal children of comparable ages. Considerations that led to our choice of

Richard A. Olshen; Edmund N. Biden; Marilynn P. Wyatt; David H. Sutherland

1989-01-01

125

Gait analysis methods in rehabilitation  

Microsoft Academic Search

INTRODUCTION: Brand's four reasons for clinical tests and his analysis of the characteristics of valid biomechanical tests for use in orthopaedics are taken as a basis for determining what methodologies are required for gait analysis in a clinical rehabilitation context. MEASUREMENT METHODS IN CLINICAL GAIT ANALYSIS: The state of the art of optical systems capable of measuring the positions of

Richard Baker; Hugh Williamson; Gait CCRE

2006-01-01

126

Clinical gait analysis: A review  

Microsoft Academic Search

Gait analysis has now advanced to the point where it is used as a routine part of patient management in certain centers. It is best thought of as a special investigation, which is used together with the history, physical examination and other special investigations to perform a detailed assessment of a patient with a walking disorder. Clinical gait analysis usually

Michael W. Whittle

1996-01-01

127

`An observational report of intensive robotic and manual gait training in sub-acute stroke  

PubMed Central

Background The use of automated electromechanical devices for gait training in neurological patients is increasing, yet the functional outcomes of well-defined training programs using these devices and the characteristics of patients that would most benefit are seldom reported in the literature. In an observational study of functional outcomes, we aimed to provide a benchmark for expected change in gait function in early stroke patients, from an intensive inpatient rehabilitation program including both robotic and manual gait training. Methods We followed 103 sub-acute stroke patients who met the clinical inclusion criteria for Body Weight Supported Robotic Gait Training (BWSRGT). Patients completed an intensive 8-week gait-training program comprising robotic gait training (weeks 0-4) followed by manual gait training (weeks 4-8). A change in clinical function was determined by the following assessments taken at 0, 4 and 8 weeks (baseline, mid-point and end-point respectively): Functional Ambulatory Categories (FAC), 10 m Walking Test (10 MWT), and Tinetti Gait and Balance Scales. Results Over half of the patients made a clinically meaningful improvement on the Tinetti Gait Scale (> 3 points) and Tinetti Balance Scale (> 5 points), while over 80% of the patients increased at least 1 point on the FAC scale (0-5) and improved walking speed by more than 0.2 m/s. Patients responded positively in gait function regardless of variables gender, age, aetiology (hemorrhagic/ischemic), and affected hemisphere. The most robust and significant change was observed for patients in the FAC categories two and three. The therapy was well tolerated and no patients withdrew for factors related to the type or intensity of training. Conclusions Eight-weeks of intensive rehabilitation including robotic and manual gait training was well tolerated by early stroke patients, and was associated with significant gains in function. Patients with mid-level gait dysfunction showed the most robust improvement following robotic training.

2012-01-01

128

Gait analysis in forensic medicine*.  

PubMed

Recordings from video surveillance systems are used as evidence from crime scenes. It would be useful to perform comparisons between disguised perpetrators and suspects based on their gait. We applied functional anatomical and biomechanical knowledge to analyze the gait of perpetrators, as recorded on surveillance video. Using a structured checklist, which addresses the single body segments during gait, we were able to give a statement concerning the gait patterns. Characteristic parameters were, e.g., varus instability in the knee at heel strike, and larger lateral flexion of the spinal column to one side than the other. Based on these characteristic features, we are able to state with reasonable certainty whether the suspect could be the perpetrator, but it is not possible to identify the perpetrator positively. Nevertheless, we have been involved in several cases where the court has found that this type of gait analysis was a valuable tool. PMID:18636978

Larsen, Peter K; Simonsen, Erik B; Lynnerup, Niels

2008-09-01

129

Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training  

Microsoft Academic Search

BACKGROUND: Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on

Alexander Duschau-Wicke; Andrea Caprez; Robert Riener

2010-01-01

130

Individual Recognition Using Gait Energy Image  

Microsoft Academic Search

In this paper, we propose a new spatio-temporal gait representation, called Gait Energy Image (GEI), to characterize human walking properties for individual recognition by gait. To address the problem of the lack of training templates, we also propose a novel approach for human recognition by combining statistical gait features from real and synthetic templates. We directly compute the real templates

Ju Han; Bir Bhanu

2006-01-01

131

PRWGEI: Poisson random walk based gait recognition  

Microsoft Academic Search

Recently, gait recognition has received much in- creased attention from biometrics researchers. Most of the literature shows that existing appearance based gait feature rep- resentation methods, however, suffer from clothing and carrying object covariate factors. Some new gait feature representations are proposed to overcome the issue of clothing and carrying covariate factors, e.g. Gait Entropy Image (GEnI). Even though these

Pratheepan Yogarajah; Joan V. Condell; Girijesh Prasad

2011-01-01

132

Effects of a lower-body exoskeleton device on metabolic cost and gait biomechanics during load carriage.  

PubMed

This study investigated the effects on metabolic cost and gait biomechanics of using a prototype lower-body exoskeleton (EXO) to carry loads. Nine US Army participants walked at 1.34 m/s on a 0% grade for 8 min carrying military loads of 20 kg, 40 kg and 55 kg with and without the EXO. Mean oxygen consumption (VO(2)) scaled to body mass and scaled to total mass were significantly higher, by 60% and 41% respectively, when the EXO was worn, compared with the control condition. Mean VO(2) and mean VO(2) scaled to body mass significantly increased with load. The kinematic and kinetic data revealed significant differences between EXO and control conditions, such as walking with a more flexed posture and braking with higher ground reaction force at heel strike when wearing the EXO. Study findings demonstrate that the EXO increased users' metabolic cost while carrying various loads and altered their gait biomechanics compared with conventional load carriage. STATEMENT OF RELEVANCE: An EXO designed to assist in load bearing was found to raise energy expenditure substantially when tested by soldiers carrying military loads. EXO weight, weight distribution and design elements that altered users' walking biomechanics contributed to the high energy cost. To realise the potential of EXOs, focus on the user must accompany engineering advances. PMID:20865609

Gregorczyk, Karen N; Hasselquist, Leif; Schiffman, Jeffrey M; Bensel, Carolyn K; Obusek, John P; Gutekunst, David J

2010-10-01

133

Intoeing gait in children.  

PubMed

OBJECTIVE: To review the aetiology and management of intoeing. DATA SOURCES: Medline and non-Medline literature search, and personal experience. STUDY SELECTION: Studies that provided evidence-based information about the aetiology and management of paediatric intoeing gait were selected. DATA EXTRACTION: Data were extracted and reviewed independently by both authors. DATA SYNTHESIS: An intoeing gait affects many children and, as with flexible flatfoot, bowleg, and knock-knee, it falls into the category of physiological problems that occur in normal children. The usual causes are excessive femoral anteversion, internal tibial torsion, and metatarsus adductus. Management is based on understanding the causes and the natural course of the condition and the effectiveness of various treatment modalities. Unfortunately, due to poor understanding of the condition, intoeing is commonly overtreated with braces or special footwear. CONCLUSIONS: Intoeing is one of the most common conditions encountered in paediatric orthopaedic practice. It is important to make an early diagnosis of pathological causes of intoeing such as cerebral palsy and developmental dysplasia of the hips so that treatment can be commenced as soon as possible. PMID:10870163

Li; Leong

1999-12-01

134

[Gait changes and fall risk].  

PubMed

Walking is a complex motor task generally performed automatically by older adults. Falls with or without serious consequences such as fractures or fear of falling can be the result. Gait analysis shows that even minor stride-to-stride variations increase the risk for falls. These gait changes are often too small to be detected during normal walking alone, but rather appear in combination with an additional task, the so-called dual tasking. Irregular gait is not an inevitability of older age, but can be improved by targeted interventions. PMID:22294303

Wolf, I; Bridenbaugh, S A; Gschwind, Y J; Kressig, R W

2012-02-01

135

Gait changes caused by the habits and methods of carrying a handbag.  

PubMed

[Purpose] The purpose of this study was to provide information to help maintain correct posture by identifying gait changes caused by the habits and methods of carrying bags. [Method] The subjects were 34 healthy right-handed women. Among them, 18 subjects had the habit of carrying bags on their right side, and 16 subjects had the habit of carrying bags on their left side. The subjects were instructed to walk while carrying a bag, which weighted approximately 10% of the subjects' average weight, in four different ways; holding it in the left hand, carrying it over the left shoulder, holding it in the right hand, and carrying it over the right shoulder. The subjects' gaits were measured using a gait analyzer. [Results] Subjects who habitually carried bags on their right exhibited changes in gait variables related to walking distance. In addition, their gait velocities were relatively faster. On the other hand, differences in temporal and spatial gait variables were not exhibited when the bag was carried using the four methods. [Conclusion] When the weight of a bag is appropriate, bag-carrying habits had significant effects on gaits. Therefore, people who carry bags should avoid the habit of carrying them on only one side. PMID:24259895

Son, Sungmin; Noh, Hyolyun

2013-08-01

136

Minimal detectable change for gait variables collected during treadmill walking in individuals post-stroke  

PubMed Central

Post-stroke gait impairments are common and result in slowed walking speeds and decreased community participation post-stroke. Treadmill training has recently emerged as an effective gait rehabilitation intervention. Furthermore, kinematic and kinetic data collected during treadmill walking are commonly used for assessing gait performance. The minimal detectable change (MDC) for gait variables provides a useful index to determine whether the magnitude of change in gait produced after an intervention is greater than the amount of change attributable to day-to-day variability in gait or test–retest measurement errors. The MDC values for kinematic, ground reaction force (GRF), spatial, and temporal variables collected during treadmill walking post-stroke have not been previously reported. The objective of this study was, therefore, to compute MDCs for post-stroke gait kinematics, GRF indices, temporal, and spatial measures during treadmill walking. Nineteen individuals with chronic post-stroke hemiparesis (12 males; age = 47–75 years; 72.6 ± 63.4 months since stroke) participated in 2 testing sessions separated by 20.7 ± 26.8 days. Our results showed that test–retest reliability was excellent for all gait variables tested (intraclass correlation coefficients = 0.799–0.986). MDCs were reported for hip, knee, and ankle joint angles (range 3.8° for trailing limb angles to 11.5° for hip extension), peak anterior GRF (2.85% body weight), mean vertical GRF (4.65% body weight), all temporal variables (range 3.2–4.2% gait cycle), and paretic step length (6.7 cm). These MDCs provide a useful reference to help interpret the magnitudes of changes in post-stroke gait variables.

Kesar, Trisha M.; Binder-Macleod, Stuart A.; Hicks, Gregory E.; Reisman, Darcy S.

2011-01-01

137

Gait analysis in forensic medicine  

Microsoft Academic Search

ABSTRACT We have combined,the basic human,ability to recognize other individuals with functional anatomical and biomechanical knowledge, in order to analyze the gait of perpetrators as recorded on surveillance video. The perpetrators are then compared,with similar analyses of suspects. At present we give,a statement to the police as to whether the perpetrator has a characteristicgait pattern compared to normal gait, and

Peter K. Larsen; Erik B. Simonsen; Niels Lynnerup

138

Changes in Midbrain Pain Receptor Expression, Gait and Behavioral Sensitivity in a Rat Model of Radiculopathy  

PubMed Central

Intervertebral disc herniation may contribute to inflammatory processes that associate with radicular pain and motor deficits. Molecular changes at the affected dorsal root ganglion (DRG), spinal cord, and even midbrain, have been documented in rat models of radiculopathy or nerve injury. The objective of this study was to evaluate gait and the expression of key pain receptors in the midbrain in a rodent model of radiculopathy. Radiculopathy was induced by harvesting tail nucleus pulposus (NP) and placing upon the right L5 DRG in rats (NP-treated, n=12). Tail NP was discarded in sham-operated animals (n=12). Mechanical allodynia, weight-bearing, and gait were evaluated in all animals over time. At 1 and 4 weeks after surgery, astrocyte and microglial activation was tested in DRG sections. Midbrain sections were similarly evaluated for immunoreactivity to serotonin (5HT2B), mu-opioid (µ-OR), and metabotropic glutamate (mGluR4 and 5) receptor antibodies. NP-treated animals placed less weight on the affected limb 1 week after surgery and experienced mechanical hypersensitivity over the duration of the study. Astroctye activation was observed at DRGs only at 4 weeks after surgery. Findings for pain receptors in the midbrain of NP-treated rats included an increased expression of 5HT2B at 1, but not 4 weeks; increased expression of µ-OR and mGluR5 at 1 and 4 weeks (periaqueductal gray region only); and no changes in expression of mGluR4 at any point in this study. These observations provide support for the hypothesis that the midbrain responds to DRG injury with a transient change in receptors regulating pain responses.

Hwang, Priscilla Y; Allen, Kyle D; Shamji, Mohammed F; Jing, Liufang; Mata, Brian A; Gabr, Mostafa A; Huebner, Janet L; Kraus, Virginia B; Richardson, William J; Setton, Lori A

2012-01-01

139

Polar Bears  

NSDL National Science Digital Library

Use the following websites to answer questions about the rapid disappearance of polar bears in the Arctic region. Polar Bear picture Polar Bear Tracker 1: What region in the world has the fewest polar bears? 2: Using the internet as a resource, provide some reasons as to why this region is suffering from the most polar bear differences? Polar Bears Change Diet 1: Why are polar bears having to change their diets? 2: List some other factors (besides diet) in the ...

Thomas, Mr.

2010-09-27

140

Gait analysis of spinal cord injured subjects: Effects of injury level and spasticity  

Microsoft Academic Search

Objective: To identify abnormalities in the gait of spinal cord injured (SCI) subjects, particularly in relation to injury level and spasticity.Design: Case-control study comparing the gait of SCI individuals with matched controls. Video-motion analysis was used to collect data on temporal and kinematic variables. Spasticity was assessed using the Ashworth score and pendulum test. Data regarding age, height, weight, mechanism,

Patricia Krawetz; Patricia Nance

1996-01-01

141

Gait assessment in dairy cattle.  

PubMed

Lameness is one of the most important dairy cow welfare issues and has inspired a growing body of literature on gait assessment. Validation studies have shown that several methods of gait assessment are able to successfully distinguish cows with and without painful pathologies. While subjective methods provide an immediate, on-site assessment and require no technical equipment, they show variation in observer reliability. On the other hand, objective methods of gait assessment provide accurate and reliable data, but typically require sophisticated technology, limiting their use on farms. In this critical review, we evaluate gait assessment methods, discuss the reliability and validity of measures used to date, and point to areas where new research is needed. We show how gait can be affected by hoof and leg pathologies, treatment of these ailments and the pain associated with lameness. We also discuss how cow (e.g. conformation, size and udder fill) and environmental features (e.g. flooring) contribute to variation in the way cows walk. An understanding of all these factors is important to avoid misclassifying of cows and confounding comparisons between herds. PMID:22444175

Flower, F C; Weary, D M

2009-01-01

142

Gait analysis in forensic medicine  

NASA Astrophysics Data System (ADS)

We have combined the basic human ability to recognize other individuals with functional anatomical and biomechanical knowledge, in order to analyze the gait of perpetrators as recorded on surveillance video. The perpetrators are then compared with similar analyses of suspects. At present we give a statement to the police as to whether the perpetrator has a characteristic gait pattern compared to normal gait, and if a suspect has a comparable gait pattern. We have found agreements such as: limping, varus instability in the knee at heel strike, larger lateral flexion of the spinal column to one side than the other, inverted ankle during stance, pronounced sagittal head-movements, and marked head-shoulder posture. Based on these characteristic features, we state whether suspect and perpetrator could have the same identity but it is not possible to positively identify the perpetrator. Nevertheless, we have been involved in several cases where the court has found that this type of gait analysis, especially combined with photogrammetry, was a valuable tool. The primary requisites are surveillance cameras recording with sufficient frequency, ideally about 15 Hz, which are positioned in frontal and preferably also in profile view.

Larsen, Peter K.; Simonsen, Erik B.; Lynnerup, Niels

2007-01-01

143

Simulations of skin and subcutaneous tissue loading in the buttocks while regaining weight-bearing after a push-up in wheelchair users.  

PubMed

Pressure ulcers (PUs) are common in patients who chronically depend on a wheelchair for mobility, such as those with a spinal cord injury (SCI). In attempt to prevent the formation of PUs, pressure relieving maneuvers, such as push-ups, are commonly recommended for individuals with SCI. However, very little is known about skin and subcutaneous fat tissue load distributions during sitting and in particular their development during the process of regaining weight-bearing after a push-up. Knowledge on how these loads evolve during sitting-down is critical for understanding the susceptibility of skin to PUs. Considering the potential practical implications on guidelines for wheelchair users, we studied herein the build-up of shear loads in skin and subcutaneous fat using a model of the buttocks of a single SCI subject. Using 12 variants of our finite element (FE) model, we determined the shear loads in skin and subcutaneous fat tissues under the ischial tuberosities when sitting down on foam cushions with different stiffness properties, in healthy skin and scarred skin conditions, focusing on the time course of the build-up of tissue loads. We found substantial differences between the loading curves of skin and fat: While the fat was loaded at a nearly constant rate, skin loads increased nonlinearly - with a greater load/time slope at early skin-support contact. In the context of tissue health and prevention of PUs, this indicates that the more sensitive period with respect to skin integrity is at initial skin-support contact. We further found that the edges of a pre-existing scar are more susceptible to injury, and the greater risk for that is when a hypertrophic scar is present. Despite that this is a theoretical modeling study with associated limitations, we believe that it is already appropriate to recommend to patients to reposition themselves gradually and gently, and not to "fall" back into the wheelchair after finishing a push-up maneuver. PMID:23706990

Levy, Ayelet; Kopplin, Kara; Gefen, Amit

2013-12-01

144

Motor imagery of gait tasks in individuals with Parkinson disease.  

PubMed

We developed a questionnaire to assess motor imagery (MI) of gait and administered it to 33 controls and 28 individuals with PD. Our goals were: 1) compare gait MI in individuals with and without PD, 2) determine whether walking performance relates to gait MI and 3) compare gait MI in individuals with PD with and without freezing of gait. Gait MI was not different between PD and controls. There was no correlation between walking performance and gait MI, and no difference in gait MI between freezers and nonfreezers. The gait imagery questionnaire may be useful for imaging studies involving imagined gait. PMID:23939404

Pickett, Kristen A; Peterson, Daniel S; Earhart, Gammon M

2012-01-01

145

Animal Gait Generation for Quadrupedal Robot  

Microsoft Academic Search

In the field of the pet robot and robot therapy, the creatural motion is important for the robots imitated the form of various animals. This paper presents the generation method of animal gait for quadrupedal robot. Here, we have employed AIBO as experimental quadrupedal robot and created the gait of AIBO in imitation of animal gait. At first, We have

Hidekazu Suzuki; A. Aburadani; H. Nishi; Seiichi Inoue

2007-01-01

146

Performance prediction for individual recognition by gait  

Microsoft Academic Search

Existing gait recognition approaches do not give their theoretical or experimental performance predictions. There- fore, the discriminating power of gait as a feature for human recognition cannot be evaluated. In this paper, we first propose a kinematic-based approach to recognize human by gait. The proposed approach estimates 3D human walking parameters by performing a least squares fit of the 3D

Ju Han; Bir Bhanu

2005-01-01

147

[Gait analysis--a new diagnostic tool].  

PubMed

Three-dimensional gait analysis is a systematic measurement, description, and assessment of human gait. Gait analysis is established as a useful diagnostic tool in patients with gait problems, as it is not possible to obtain an adequate and detailed understanding of such a complex mechanism as gait in a conventional clinical examination. The method has provided a better understanding of both normal gait and abnormal gait patterns; it is a suitable instrument for evaluation of treatment results as well as for scientific work. The first gait laboratory for clinical use in Norway was established in 2002 in the Section for child neurology at Rikshospitalet University Hospital in Oslo, Norway. In this article the procedure for gait analysis is described and the clinical value is indicated by a case record of a child with cerebral palsy. Gait analysis has entailed a change of policy with regard to surgical treatment in this patient group. Previously, operative intervention at a single level was usual, whereas current practice involves simultaneous interventions at several levels of both lower extremities. After three years' experience we recommend gait analysis in routine diagnostics, particularly as a preoperative evaluation, in all children with gait problems and in the follow up after surgery or other treatment. PMID:16100541

Lofterød, Bjørn; Terjesen, Terje; Skaaret, Ingrid

2005-08-11

148

Gait Recognition Using Image Self-Similarity  

Microsoft Academic Search

Gait is one of the few biometrics that can be measured at a distance, and is hence useful for passive surveillance as well as biometric applications. Gait recognition research is still at its infancy, however, and we have yet to solve the fundamental issue of finding gait features which at once have su cient discrimination power and can be extracted

Chiraz BenAbdelkader; Ross G. Cutler; Larry S. Davis

2004-01-01

149

Enhancing robotic gait training via augmented feedback  

Microsoft Academic Search

Recent work has examined the feasibility of robotic-assisted gait training in pediatric patients, including children with cerebral palsy (CP). Herein we present a case series describing clinical outcomes in four children with CP who underwent gait training using a robotic driven gait orthosis (DGO) (Pediatric Lokomat©). Children had a diagnosis of spastic diplegia due to CP. They were paired based

Benjamin Patritti; Monica Sicari; Lynn Deming; Fernanda Romaguera; Marlena Pelliccio; Maria Grazia Benedetti; Donna Nimec; Paolo Bonato

2010-01-01

150

A 4-Week Neuromuscular Training Program and Gait Patterns at the Ankle Joint  

PubMed Central

Context: Previous research into the rehabilitation of ankle sprains has primarily focused on outcome measures that do not replicate functional activities, thus making it difficult to extrapolate the results relative to the weight-bearing conditions under which most ankle sprains occur. Objective: To measure the effects of a training program on gait during walking and running in an active athletic population. Design: Matched-pairs, controlled trial. Setting: University motion analysis laboratory. Patients or Other Participants: Ten subjects from an athletic population (7 healthy, 3 with functional ankle instability: age = 25.8 ± 3.9 years, height = 177.6 ± 6.1 cm, mass = 66.8 ± 7.4 kg) and 10 controls matched for age, sex, activity, and ankle instability (7 healthy, 3 with functional ankle instability: age = 27.4 ± 5.8 years, height = 178.7 ± 10.8 cm, mass = 71.6 ± 10.0 kg). Intervention(s): A 4-week neuromuscular training program undertaken by the treatment group. Main Outcome Measure(s): We measured ankle position and velocity in the frontal (x) and sagittal (y) planes in all subjects during treadmill walking and running for the periods 100 milliseconds before heel strike, at heel strike, and 100 milliseconds after heel strike. Results: A 4-week neuromuscular training program resulted in no significant changes in ankle position or velocity during treadmill walking and running. Conclusions: The mechanisms by which neuromuscular training improves function in normal subjects and those with functional ankle instability do not appear to result in measurable changes in gait kinematics. Our findings raise issues regarding methods of ankle sprain rehabilitation and the measurement of their effectiveness in improving functional activities. Further research in a larger population with functional ankle instability is necessary.

Coughlan, Garrett; Caulfield, Brian

2007-01-01

151

Visualisation of Gait Analysis Data  

Microsoft Academic Search

Modern 3D motion capture systems allow large amounts of data to be recorded from patients with walking difficulties. However, it often proves difficult for clinical staff to interpret this data to gain insight into the patient's condition. Automation and simplification of the analysis of gait data is therefore necessary if it is to be used more productively. In this paper,

Robert A. Noble; Ray White

2005-01-01

152

Reflections on clinical gait analysis  

Microsoft Academic Search

Clinical gait analysis allows the measurement and assessment of walking biomechanics, which facilitates the identification of abnormal characteristics and the recommendation of treatment alternatives. The predominant methods for this analysis currently include the tracking of external markers placed on the patient, the monitoring of patient\\/ground interaction (e.g. ground reaction forces), and the recording of muscle electromyographic (EMG) activity, all during

Roy B Davis

1997-01-01

153

Clinimetrics of freezing of gait.  

PubMed

The clinical assessment of freezing of gait (FOG) provides great challenges. Patients often do not realize what FOG really is. Assessing FOG is further complicated by the episodic, unpredictable, and variable presentation, as well as the complex relationship with medication. Here, we provide some practical recommendations for a standardized clinical approach. During history taking, presence of FOG is best ascertained by asking about the characteristic feeling of "being glued to the floor." Detection of FOG is greatly facilitated by demonstrating what FOG actually looks like, not only to the patient but also to the spouse or other carer. History taking further focuses on the specific circumstances that provoke FOG and on its severity, preferably using standardized questionnaires. Physical examination should be done both during the ON and OFF state, to judge the influence of treatment. Evaluation includes a dedicated "gait trajectory" that features specific triggers to elicit FOG (gait initiation; a narrow passage; dual tasking; and rapid 360 degrees axial turns in both directions). Evaluating the response to external cues has diagnostic importance, and helps to determine possible therapeutic interventions. Because of the tight interplay between FOG and mental functions, the evaluation must include cognitive testing (mainly frontal executive functions) and judgment of mood. Neuroimaging is required for most patients in order to detect underlying pathology, in particular lesions of the frontal lobe or their connections to the basal ganglia. Various quantitative gait assessments have been proposed, but these methods have not proven value for clinical practice. PMID:18668628

Snijders, Anke H; Nijkrake, Maarten J; Bakker, Maaike; Munneke, Marten; Wind, Carina; Bloem, Bastiaan R

2008-01-01

154

The gait system research of intelligent bionic leg  

Microsoft Academic Search

Intelligent bionic legs (IBL) controlled by magneto-rheological (MR) damper is an advanced prosthesis. The conception, research purpose and configuration of intelligent bionic leg were introduced. Gait description of human normal gait is detailed using analysis method of finite state machine (FMS). By information gained from six-axis force sensor, the gait perception method of typical gait events and gait states is

Hualong Xie; Fei Li; Zhongqi Sheng; Zhiwei Xu; Yongxian Liu

2009-01-01

155

Optimum energy loss in electro magnetic bearing  

Microsoft Academic Search

This paper includes weight optimization method of rotor and analysis of total power loss in radial magnetic bearing consisting of four, eight and twelve poles. Weight optimization reduces copper loss in bearing since the electromagnetic force is reduced due to optimized rotor. Further numbers of poles in magnetic bearing are varied for same electromagnetic force 350 N and stator is

Santosh Shelke; R. V. Chalam

2011-01-01

156

Cerebral Palsy Gait, Clinical Importance  

PubMed Central

ABSTRACT Cerebral palsy refers to a lesion on an immature brain, that determines permanent neurological disorders. Knowing the exact cause of the disease does not alter the treatment management. The etiology is 2-2.5/1000 births and the rate is constant in the last 40-50 years because advances in medical technologies have permitted the survival of smaller and premature new born children. Gait analysis has four directions: kinematics (represents body movements analysis without calculating the forces), kinetics (represents body moments and forces), energy consumption (measured by oximetry), and neuromuscular activity (measured by EMG). Gait analysis can observe specific deviations in a patient, allowing us to be more accurate in motor diagnoses and treatment solutions: surgery intervention, botulinum toxin injection, use of orthosis, physical kinetic therapy, oral medications, baclofen pump.

TUGUI, Raluca Dana; ANTONESCU, Dinu

2013-01-01

157

Performance analysis for gait in camera networks  

Microsoft Academic Search

ABSTRACT This paper deploys gait analysis for subject identication in multi-camera surveillance scenarios. We present a new method,for viewpoint independent markerless gait analysis that does not require camera,calibration and works with a wide range of directions of walking. These properties make the proposed method,particularly suitable for gait identi- cation in real surveillance scenarios where people and their behaviour need to

Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

2008-01-01

158

Lever arm dysfunction in cerebral palsy gait.  

PubMed

Skeletal structures act as lever arms during walking. Muscle activity and the ground reaction against gravity exert forces on the skeleton, which generate torque (moments) around joints. These lead to the sequence of movements which form normal human gait. Skeletal deformities in cerebral palsy (CP) affect the function of bones as lever arms and compromise gait. Lever arm dysfunction should be carefully considered when contemplating treatment to improve gait in children with CP. PMID:24432098

Theologis, Tim

2013-11-01

159

Gait Analysis and Human Motion Tracking  

Microsoft Academic Search

\\u000a We present a strategy based on human gait to achieve efficient tracking, recovery of ego-motion and 3-D reconstruction from\\u000a an image sequence acquired by a single camera attached to a pedestrian. In the first phase, the parameters of the human gait\\u000a are established by a classical frame-by-frame analysis, using an generalised least squares (GLS) technique. The gait model\\u000a is non-linear,

Huiyu Zhou

160

Gait Analysis in the Mouse  

Microsoft Academic Search

The gait of the adult Swiss (Mike Flack—MF1 subtype) mouse during spontaneous walk\\/trot locomotion at velocities ranging from 14–43 cm s?1 has been analysed using simultaneous video and reaction force analysis. No differences were observed between males and females. Velocity adjustments within this range are accounted for to a greater extent (>70%) by stride time decreases and to a lesser

K. A Clarke; J Still

1999-01-01

161

Gait Analysis Laboratory  

NASA Technical Reports Server (NTRS)

Complete motion analysis laboratory has evolved out of analyzing walking patterns of crippled children at Stanford Children's Hospital. Data is collected by placing tiny electrical sensors over muscle groups of child's legs and inserting step-sensing switches in soles of shoes. Miniature radio transmitters send signals to receiver for continuous recording of abnormal walking pattern. Engineers are working to apply space electronics miniaturization techniques to reduce size and weight of telemetry system further as well as striving to increase signal bandwidth so analysis can be performed faster and more accurately using a mini-computer.

1976-01-01

162

Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait.  

PubMed

Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between planning and imagining a movement. In addition, it avoids confounds introduced by brain responses to altered motor performance and somatosensory feedback during actual freezing episodes. We included 24 patients with Parkinson's disease: 12 patients with freezing of gait, 12 matched patients without freezing of gait and 21 matched healthy controls. Subjects performed two previously validated tasks--motor imagery of gait and a visual imagery control task. During functional magnetic resonance imaging scanning, we quantified imagery performance by measuring the time required to imagine walking on paths of different widths and lengths. In addition, we used voxel-based morphometry to test whether between-group differences in imagery-related activity were related to structural differences. Imagery times indicated that patients with freezing of gait, patients without freezing of gait and controls engaged in motor imagery of gait, with matched task performance. During motor imagery of gait, patients with freezing of gait showed more activity than patients without freezing of gait in the mesencephalic locomotor region. Patients with freezing of gait also tended to have decreased responses in mesial frontal and posterior parietal regions. Furthermore, patients with freezing of gait had grey matter atrophy in a small portion of the mesencephalic locomotor region. The gait-related hyperactivity of the mesencephalic locomotor region correlated with clinical parameters (freezing of gait severity and disease duration), but not with the degree of atrophy. These results indicate that patients with Parkinson's disease with freezing of gait have structural and functional alterations in the mesencephalic locomotor region. We suggest that freezing of gait might emerge when altered cortical control of gait is combined with a limited ability of the mesencephalic locomotor region to react to that alteration. These limitations might become particularly evident during challenging events that require precise regulation of step length and gait timing, such as turning or initiating walking, which are known triggers for freezing of gait. PMID:21126990

Snijders, Anke H; Leunissen, Inge; Bakker, Maaike; Overeem, Sebastiaan; Helmich, Rick C; Bloem, Bastiaan R; Toni, Ivan

2011-01-01

163

Optics in gait analysis and anthropometry  

NASA Astrophysics Data System (ADS)

Since antiquity, human gait has been studied to understand human movement, the kind of gait, in some cases, can cause musculoskeletal disorders or other health problems; in addition, also from antiquity, anthropometry has been important for the design of human items such as workspaces, tools, garments, among others. Nowadays, thanks to the development of optics and electronics, more accurate studies of gait and anthropometry can be developed. This work will describe the most important parameters for gait analysis, anthropometry and the optical systems used.

Silva Moreno, Alejandra Alicia

2013-11-01

164

Polar Bear  

NSDL National Science Digital Library

This site from the World Wildlife Fund (WWF) International provides general information about polar bears as well as data on the movements of two radio-collared bears, along with the ice status, through a series of online maps.

2007-01-01

165

Gear bearings  

NASA Technical Reports Server (NTRS)

A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission.

Vranish, John M. (Inventor)

2003-01-01

166

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements  

PubMed Central

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods.

Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, Andre

2012-01-01

167

Four Essential Tremor Cases with Moderately Impaired Gait: How Impaired can Gait be in this Disease?  

PubMed Central

Background A body of literature is emerging regarding gait/balance impairments observed in essential tremor (ET) patients. Although impairment is generally mild, the full extent of the spectrum remains undefined. We present four ET cases with more severe gait/balance impairment. Methods A battery of subjective and objective gait/balance assessments was performed: the Activities-specific Balance Confidence Scale, the Berg Balance Scale, and the Tinetti Performance Oriented Mobility Assessment (POMA). Tandem missteps during 10 steps were counted. Quantitative gait testing was performed (GAITRite) to quantify gait speed, dynamic balance, gait symmetry, and gait variability. Results Two patients were middle-aged (38 and 52 years) and two were older (70 and 79 years). All had longstanding classic ET (duration 22–60 years). The mean POMA score was 21.5, which is indicative of moderate fall risk. On average, there were five missteps during tandem gait, which was higher than observed in substantially older ET cases (age 86.0±4.6 years), and four times higher than seen in ET patients of comparable age. On quantitative gait analysis, patients demonstrated significant balance impairment. Discussion We present a sample of ET patients with a level of gait difficulty that would not be characterized as mild. The existence of such cases raises a number of questions, one of which is how impaired can gait be in ET?

Louis, Elan D.; Galecki, Monica; Rao, Ashwini K.

2013-01-01

168

Biofeedback in gait training with the robotic orthosis Lokomat.  

PubMed

Neurological diseases - such as spinal cord injury, stroke and traumatic brain injury - frequently result in gait impairment The recovery of the walking ability requires functional training (i.e. walking), as previous research in man and animal has shown. Because the patient usually has reduced voluntary muscle force early after the incident, his/her movements require external support by physical therapists or special robotic devices. The Lokomat is a robotic gait orthosis with electromechanical drives that supports walking on a treadmill with body weight support. Because the movements are performed according to a predefined trajectory, there is no visible cue to the amount the patient is contributing. However, the forces measured within the drives can deliver an estimation of this contribution. Based on these measurements, biofeedback on the patient's gait performance was added as a new feature. The visual display will allow the patient to get direct feedback on his/her efforts, and will allow the therapist to instruct the patient better. We report here that the biofeedback can correctly reflect the activity of a healthy subject, that patients can benefit from the use, and what the patients' opinion is. PMID:17271408

Lünenburger, L; Colombo, Gery; Riener, Robert; Dietz, Volker

2004-01-01

169

Markerless Human Motion Capture for Gait Analysis  

Microsoft Academic Search

The aim of our study is to detect balance disorders and a tendency towards the falls in the elderly, knowing gait parameters. In this paper we present a new tool for gait analysis based on markerless human motion capture, from camera feeds. The system introduced here, recovers the 3D positions of several key points of the human body while walking.

Jamal Saboune; François Charpillet

2005-01-01

170

3D Gait Recognition Using Multiple Cameras  

Microsoft Academic Search

Gait recognition is used to identify individuals in image sequences by the way they walk. Nearly all of the approaches proposed for gait recognition are 2D methods based on analyzing image sequences captured by a single camera. In this paper, video sequences captured by multiple cameras are used as input, and then a human 3D model is set up. The

Guoying Zhao; Guoyi Liu; Hua Li; Matti Pietikäinen

2006-01-01

171

Factored Interval Particle Filtering for Gait Analysis  

Microsoft Academic Search

Commercial gait analysis systems rely on wearable sensors. The goal of this study is to develop a low cost marker less human motion capture tool. Our method is based on the estimation of 3d movements using video streams and the projection of a 3d human body model. Dynamic parameters only depend on human body movement constraints. No trained gait model

Jamal Saboune; C. Rose; F. Charpillet

2007-01-01

172

Diabetic Foot Biomechanics and Gait Dysfunction  

PubMed Central

Background Diabetic foot complications represent significant morbidity and precede most of the lower extremity amputations performed. Peripheral neuropathy is a frequent complication of diabetes shown to affect gait. Glycosylation of soft tissues can also affect gait. The purpose of this review article is to highlight the changes in gait for persons with diabetes and highlight the effects of glycosylation on soft tissues at the foot–ground interface. Methods PubMed, the Cochrane Library, and EBSCOhost® on-line databases were searched for articles pertaining to diabetes and gait. Bibliographies from relevant manuscripts were also searched. Findings Patients with diabetes frequently exhibit a conservative gait strategy where there is slower walking speed, wider base of gait, and prolonged double support time. Glycosylation affects are observed in the lower extremities. Initially, skin thickness decreases and skin hardness increases; tendons thicken; muscles atrophy and exhibit activation delays; bones become less dense; joints have limited mobility; and fat pads are less thick, demonstrate fibrotic atrophy, migrate distally, and may be stiffer. Interpretation In conclusion, there do appear to be gait changes in patients with diabetes. These changes, coupled with local soft tissue changes from advanced glycosylated end products, also alter a patient’s gait, putting them at risk of foot ulceration. Better elucidation of these changes throughout the entire spectrum of diabetes disease can help design better treatments and potentially reduce the unnecessarily high prevalence of foot ulcers and amputation.

Wrobel, James S.; Najafi, Bijan

2010-01-01

173

Enhancing robotic gait training via augmented feedback.  

PubMed

Recent work has examined the feasibility of robotic-assisted gait training in pediatric patients, including children with cerebral palsy (CP). Herein we present a case series describing clinical outcomes in four children with CP who underwent gait training using a robotic driven gait orthosis (DGO) (Pediatric Lokomat©). Children had a diagnosis of spastic diplegia due to CP. They were paired based on functional abilities and observed gait characteristics. Two children had a GMFCS of III and showed excessive ankle plantarflexion during stance. The other two children had a GMFCS of II and displayed a crouch gait pattern. Each subject participated in a 6-week intervention of robotic-assisted gait training that involved three 30-minute sessions per week. Pre-and post-training evaluations were performed including clinical tests of standing and walking function, walking speed, and walking endurance. Clinical gait analysis was also performed using a motion capture system to assess changes in gait mechanics. All subjects showed an improvement in locomotor function. For lower functioning children, this may be mediated by improved trunk control. The use of augmented feedback was associated with larger. However, these results have to be considered with caution because of the limited sample size of the study. PMID:21097013

Patritti, Benjamin; Sicari, Monica; Deming, Lynn; Romaguera, Fernanda; Pelliccio, Marlena; Benedetti, Maria Grazia; Nimec, Donna; Bonato, Paolo

2010-01-01

174

Gait Sequence Analysis Using Frieze Patterns  

Microsoft Academic Search

ABSTRACT We analyze walking people using a gait sequence representation that bypasses the need for frame - to - frame tracking of body parts The gait representation maps a video sequence of silhou - ettes into a pair of two - dimensional spatio - temporal patterns that are periodic along the time axis Mathematically, such patterns are called \\

Yanxi Liu; Robert T. Collins; Yanghai Tsin

2002-01-01

175

Gait Analysis for Recognition and Classification  

Microsoft Academic Search

This paper describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple features such as moments extracted from orthogonal view video silhouettes of human walking motion. Despite its simplicity, the re- sulting feature vector contains enough information to per- form well on human identification and gender classification tasks. We

L. Lee; W. Eric L. Grimson

2002-01-01

176

Propulsive adaptation to changing gait speed  

Microsoft Academic Search

Understanding propulsion and adaptation to speed requirements is important in determining appropriate therapies for gait disorders. We hypothesize that adaptations for changing speed requirements occur primarily at the hip. The slow, normal and fast gait of 24 healthy young subjects was analyzed. The linear power was analyzed at the hip joint. The anterior–posterior and vertical induced accelerations of the hip

Patrick O Riley; Ugo Della Croce; D Casey Kerrigan

2001-01-01

177

Safety concept for robotic gait trainers  

Microsoft Academic Search

The work presents a newly developed safety concept for application of robotic walking simulators based on the principle of programmable footplates in gait rehabilitation. Unlike robotic hand devices or exoskeleton robots for gait training on treadmills, which can be built relatively lightweight and require only small drives which can hardly do harm to the patient, a programmable footplate walking simulator

H. Schmidt; S. Hesse; R. Bernhardt

2004-01-01

178

Average Gait Differential Image Based Human Recognition  

PubMed Central

The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition.

Chen, Jinyan; Liu, Jiansheng

2014-01-01

179

Research on gait-based human identification  

NASA Astrophysics Data System (ADS)

Gait recognition refers to automatic identification of individual based on his/her style of walking. This paper proposes a gait recognition method based on Continuous Hidden Markov Model with Mixture of Gaussians(G-CHMM). First, we initialize a Gaussian mix model for training image sequence with K-means algorithm, then train the HMM parameters using a Baum-Welch algorithm. These gait feature sequences can be trained and obtain a Continuous HMM for every person, therefore, the 7 key frames and the obtained HMM can represent each person's gait sequence. Finally, the recognition is achieved by Front algorithm. The experiments made on CASIA gait databases obtain comparatively high correction identification ratio and comparatively strong robustness for variety of bodily angle.

Li, Youguo

180

Optimal Synchronizability of Bearings  

NASA Astrophysics Data System (ADS)

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine-tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)PLEEE81539-3755]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, m˜r?, with an optimal exponent ?=?× which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors.

Araújo, N. A. M.; Seybold, H.; Baram, R. M.; Herrmann, H. J.; Andrade, J. S., Jr.

2013-02-01

181

Weight Bearing through Lower Limbs in a Standing Frame with and without Arm Support and Low-Magnitude Whole Body Vibration in Men and Women with Complete Motor Paraplegia  

PubMed Central

Objective To determine the proportion of body weight (BW) borne through the lower limbs in persons with complete, motor paraplegia using a standing frame, with and without support of their arms. We also examined the effect of low-magnitude whole body vibration on loads borne by the lower extremities. Design Vertical ground reaction forces (GRF) were measured in 11 participants (6 men and 5 women) with paraplegia of traumatic origin (injury level T3 to T12) standing on a low-magnitude vibrating plate using a standing frame. GRF were measured in four conditions: 1) no vibration with arms on standing frame tray; 2) no vibration with arms at side; 3) vibration with arms on tray; 4) vibration with arms at side. Results GRF with arms on tray, without vibration, was 0.76 ± 0.07 BW. With arms at the side, GRF increased to 0.85 ± 0.12 BW. With vibration, mean GRF did not significantly differ from no-vibration conditions for either arm positions. Oscillation of GRF with vibration was significantly different from no-vibration conditions (p<0.001) but similar in both arm positions. Conclusion Men and women with paraplegia using a standing frame bear the majority of their weight through their lower limbs. Supporting their arms on the tray reduces the GRF by ~10% BW. Low-magnitude vibration provided additional oscillation of the load-bearing forces and was proportionally similar regardless of arm position.

Bernhardt, Kathie A.; Beck, Lisa A.; Lamb, Jeffry L.; Kaufman, Kenton R.; Amin, Shreyasee; Wuermser, Lisa-Ann

2014-01-01

182

The Inhibition of Subchondral Bone Lesions Significantly Reversed the Weight-Bearing Deficit and the Overexpression of CGRP in DRG Neurons, GFAP and Iba-1 in the Spinal Dorsal Horn in the Monosodium Iodoacetate Induced Model of Osteoarthritis Pain  

PubMed Central

Background Chronic pain is the most prominent and disabling symptom of osteoarthritis (OA). Clinical data suggest that subchondral bone lesions contribute to the occurrence of joint pain. The present study investigated the effect of the inhibition of subchondral bone lesions on joint pain. Methods Osteoarthritic pain was induced by an injection of monosodium iodoacetate (MIA) into the rat knee joint. Zoledronic acid (ZOL), a third generation of bisphosphonate, was used to inhibit subchondral bone lesions. Joint histomorphology was evaluated using X-ray micro computed tomography scanning and hematoxylin-eosin staining. The activity of osteoclast in subchondral bone was evaluated using tartrate-resistant acid phosphatase staining. Joint pain was evaluated using weight-bearing asymmetry, the expression of calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG), and spinal glial activation status using glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule-1 (Iba-1) immunofluorescence. Afferent neurons in the DRGs that innervated the joints were identified using retrograde fluorogold labeling. Results MIA injections induced significant histomorphological alterations and joint pain. The inhibition of subchondral bone lesions by ZOL significantly reduced the MIA-induced weight-bearing deficit and overexpression of CGRP in DRG neurons, GFAP and Iba-1 in the spinal dorsal horn at 3 and 6 weeks after MIA injection; however, joint swelling and synovial reaction were unaffected. Conclusions The inhibition of subchondral bone lesions alleviated joint pain. Subchondral bone lesions should be a key target in the management of osteoarthritic joint pain.

Liu, Ming; Zhao, Xin; Wang, Xiaoqing; Li, Yang; Mao, Yuanqing; Zhu, Zhenan

2013-01-01

183

Pathology Case Study: Gait Disorders  

NSDL National Science Digital Library

This is a case study presented by the University of Pittsburgh Department of Pathology, which describes a 62-year-old woman with a 20-year history of gait disorders and dizziness. Visitors are given patient history, laboratory findings, along with microscopic descriptions, including images, and are given the opportunity to diagnose the patient. A "Final Diagnosis" section provides a discussion of the findings as well as references. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose disease. It is also a helpful site for educators to use to introduce or test student learning in neuropathology.

2009-04-21

184

Immunostimulatory activities of a low molecular weight antitumoral polysaccharide isolated from Agaricus blazei Murill (LMPAB) in Sarcoma 180 ascitic tumor-bearing mice.  

PubMed

LMPAB is a linear beta-(1-3)-glucan we isolated from polysaccharide extract of Agaricus blazei Murill (AbM). Effects of LMPAB on splenic natural killer (NK) cell activity, splenocyte proliferation, index of spleen and thymus, IFN-gamma expression in spleen and the concentration of IL-12, IL-18 and TNF-alpha in serum of S180 ascitic tumor-bearing mice were detected. The results showed that intraperitoneal injection of LMPAB (100 mg x kg(-1) x d(-1)) significantly increased the thymus index. LMPAB augmented splenic NK cell activity in a dose-dependent manner (50-200 mg x kg(-1) x d(-1)). The concanavalin A (3 microg/ ml) stimulated splenocyte proliferation was significantly enhanced by LMPAB at dosages of 50, 100 or 200 mg x kg(-1) x d(-1). Further studies showed that LMPAB (50, 100 or 200 mg x kg(-1) x d(-1), 14d) significantly increased the production of IL-12, TNF-alpha, IL-18 and the expression IFN-gamma as determined by ELISA and immunohistochemistry, respectively. These results clearly indicate that the anti-tumor effects of LMPAB are closely associated with up-regulation of activity of NK cells, expression of IFN-gamma in spleen and the systemic level of IL-12, IL-18 and TNF-alpha in tumor-bearing mice. PMID:19694186

Niu, Ying-Cai; Liu, Ji-Cheng; Zhao, Xue-Mei; Su, Fu-Qin; Cui, Hong-Xia

2009-07-01

185

Gait analysis as a measure of neurological function in dogs  

Microsoft Academic Search

Evaluation of gait of neurologically impaired dogs is usually conducted using subjective techniques. This research was conducted to validate the use of gait analysis as an objective measure of neurological function in dogs and to develop a comprehensive gait analysis protocol using temporospatial, kinetic, kinematic, and paw pressure data thus facilitating gait analysis as a diagnostic tool for neurologically impaired

Jongmin Kim

2009-01-01

186

DRAG: a database for recognition and analasys of gait  

Microsoft Academic Search

A novel approach is proposed for creating a standardized and comprehensive database for gait analysis. The field of gait analysis is gaining increasing attention for applications such as visual surveillance, human-computer interfaces, and gait recognition and rehabilitation. Numerous algorithms have been developed for analyzing and processing gait data; however, a standard database for their systematic evaluation does not exist. Instead,

Prem Kuchi; Raghu Ram V. Hiremagalur; Helen Huang; Michael Carhart; Jiping He; Sethuraman Panchanathan

2003-01-01

187

Gait recognition: a challenging signal processing technology for biometric identification  

Microsoft Academic Search

This article provides an overview of the basic research directions in the field of gait analysis and recognition. The recent developments in gait research indicate that gait technologies still need to mature and that limited practical applications should be expected in the immediate future. At present, there is a potential for initial deployment of gait for recognition in conjunction with

N. V. Boulgouris; D. Hatzinakos; K. N. Plataniotis

2005-01-01

188

Person identification based on gait using dynamic body parameters  

Microsoft Academic Search

Gait as a behavioural biometrics has been the subject of recent investigations. One of the unique advantages of human gait is that it can be perceived from a distance. A varied range of research has been undertaken within the field of gait recognition. A gait describes the manner of a person's walking. It can be acquired at a distance and

Jasvinder Pal Singh; Sanjeev Jain

2010-01-01

189

Treadmill gait speeds correlate with physical activity counts measured by cell phone accelerometers.  

PubMed

A number of important health-related outcomes are directly related to a person's ability to maintain normal gait speed. We hypothesize that cellular telephones may be repurposed to measure this important behavior in a noninvasive, continuous, precise, and inexpensive manner. The purpose of this study was to determine if physical activity (PA) counts collected by cell phone accelerometers could measure treadmill gait speeds. We also assessed how cell phone placement influenced treadmill gait speed measures. Participants included 55 young, middle-aged, and older community-dwelling men and women. We placed cell phones as a pendant around the neck, and on the left and right wrist, hip, and ankle. Subjects then completed an individualized treadmill protocol, alternating 1 min rest periods with 5 min of walking at different speeds (0.3-11.3 km/h; 0.2-7 mi/h). No persons were asked to walk at speeds faster than what they would achieve during day-to-day life. PA counts were calculated from all sensor locations. We built linear mixed statistical models of PA counts predicted by treadmill speeds ranging from 0.8 to 6.4 km/h (0.5-4 mi/h) while accounting for subject age, weight, and gender. We solved linear regression equations for treadmill gait speed, expressed as a function of PA counts, age, weight, and gender. At all locations, cell phone PA counts were strongly associated with treadmill gait speed. Cell phones worn at the hip yielded the best predictive model. We conclude that in both men and women, cell phone derived activity counts strongly correlate with treadmill gait speed over a wide range of subject ages and weights. PMID:22475727

Carlson, Richard H; Huebner, Derek R; Hoarty, Carrie A; Whittington, Jackie; Haynatzki, Gleb; Balas, Michele C; Schenk, Ana Katrin; Goulding, Evan H; Potter, Jane F; Bonasera, Stephen J

2012-06-01

190

Effect of a robotic restraint gait training versus robotic conventional gait training on gait parameters in stroke patients.  

PubMed

Kinematic and kinetic gait parameters have never been assessed following robotic-assisted gait training in hemiparetic patients. Previous studies suggest that restraint of the non-paretic lower limb during gait training could be a useful rehabilitation approach for hemiparetic patients. The aim of this study is to compare a new Lokomat(®) asymmetrical restraint paradigm (with a negative kinematic constraint on the non-paretic limb and a positive kinematic constraint on the paretic limb) with a conventional symmetrical Lokomat(®) training in hemiparetic subjects. We hypothesized that hip and knee kinematics on paretic side would be more improved after the asymmetrical Lokomat(®) training than after the conventional training. In a prospective observational controlled study, 26 hemiparetic subjects were randomized to one of the two groups Lokomat(®) experimental gait training (LE) or Lokomat(®) conventional gait training (LC). They were assessed using 3D gait analysis before, immediately after the 20 min of gait training and following a 20-min rest period. There was a greater increase in peak knee flexion on the paretic side following LE than LC (p = 0.04), and each type of training induced different changes in vertical GRF during single-support phase on the paretic side. Several other spatiotemporal, kinematic and kinetic gait parameters were similarly improved after both types of training. Lokomat(®) restrained gait training with a negative kinematic constraint on the non-paretic limb and a positive kinematic constraint on the paretic limb appears to be an effective approach to specifically improve knee flexion in the paretic lower limb in hemiparetic patients. This study also highlights spatiotemporal, kinematic and kinetic improvements after Lokomat(®) training, in hemiparetic subjects, rarely investigated before. PMID:24212255

Bonnyaud, Céline; Zory, Raphael; Boudarham, Julien; Pradon, Didier; Bensmail, Djamel; Roche, Nicolas

2014-01-01

191

Aerospace applications of magnetic bearings  

NASA Technical Reports Server (NTRS)

Magnetic bearings have traditionally been considered for use in aerospace applications only where performance advantages have been the primary, if not only, consideration. Conventional wisdom has been that magnetic bearings have certain performance advantages which must be traded off against increased weight, volume, electric power consumption, and system complexity. These perceptions have hampered the use of magnetic bearings in many aerospace applications because weight, volume, and power are almost always primary considerations. This paper will review progress on several active aerospace magnetic bearings programs at SatCon Technology Corporation. The magnetic bearing programs at SatCon cover a broad spectrum of applications including: a magnetically-suspended spacecraft integrated power and attitude control system (IPACS), a magnetically-suspended momentum wheel, magnetic bearings for the gas generator rotor of a turboshaft engine, a vibration-attenuating magnetic bearing system for an airborne telescope, and magnetic bearings for the compressor of a space-rated heat pump system. The emphasis of these programs is to develop magnetic bearing technologies to the point where magnetic bearings can be truly useful, reliable, and well tested components for the aerospace community.

Downer, James; Goldie, James; Gondhalekar, Vijay; Hockney, Richard

1994-01-01

192

Thrust bearing  

NASA Technical Reports Server (NTRS)

A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

Anderson, W. J. (inventor)

1976-01-01

193

Effect of Treadmill Training on Specific Gait Parameters in Older Adults with Frailty: Case Series  

PubMed Central

Background and Purpose Treadmill walking training (TWT) as an intervention to improve the gait of frail older adults has not been well studied. In this pilot study, we describe the feasibility, tolerance, and effect of TWT on specific gait parameters during overground walking in four frail older adults as a prelude to developing larger scale exercise intervention trials in this high-risk population. Case Description Four community-residing frail older individuals (age>70) with Mini-Mental Status Examination score of 26 or higher and no activity limitations. Frailty was defined as presence of at least three out of the following five attributes: slow gait (<1 m/sec), unintentional weight loss (>10 lbs in prior year), self-report of poor grip strength, exhaustion, and low level of physical activity. Intervention TWT consisted of 24 sessions (3 times/week for 8 weeks). Five quantitative gait parameters [velocity, stride length, swing time, percentage of double support phase, coefficient of variation (COV) of stride length] during overground walking were measured at baseline, weekly during training, and immediately post-TWT. Outcome All participants tolerated TWT without significant complications. Following TWT, gait velocity increased in all participants by 6.4 to 26.8 cm/sec, which was larger than the reported value for meaningful change in gait velocity (4 cm/sec). Stride length and double support phase also showed improvement in all participants (mean percentage increase of 10.8 % for stride length, and 17.1% reduction for double support phase post training compared to baseline). Swing time improved in three participants (mean reduction of 4.5 %). The COV of stride length did not show consistent improvement. Discussion This case series shows that TWT is feasible and well tolerated by frail older adults, and may improve most gait parameters in this high-risk population.

Holtzer, Roee; Mahoney, Jeannette; Wang, Cuiling; Verghese, Joe

2011-01-01

194

Motion Cue Analysis for Parkinsonian Gait Recognition  

PubMed Central

This paper presents a computer-vision based marker-free method for gait-impairment detection in Patients with Parkinson’s disease (PWP). The system is based upon the idea that a normal human body attains equilibrium during the gait by aligning the body posture with Axis-of-Gravity (AOG) using feet as the base of support. In contrast, PWP appear to be falling forward as they are less-able to align their body with AOG due to rigid muscular tone. A normal gait exhibits periodic stride-cycles with stride-angle around 45o between the legs, whereas PWP walk with shortened stride-angle with high variability between the stride-cycles. In order to analyze Parkinsonian-gait (PG), subjects were videotaped with several gait-cycles. The subject’s body was segmented using a color-segmentation method to form a silhouette. The silhouette was skeletonized for motion cues extraction. The motion cues analyzed were stride-cycles (based on the cyclic leg motion of skeleton) and posture lean (based on the angle between leaned torso of skeleton and AOG). Cosine similarity between an imaginary perfect gait pattern and the subject gait patterns produced 100% recognition rate of PG for 4 normal-controls and 3 PWP. Results suggested that the method is a promising tool to be used for PG assessment in home-environment.

Khan, Taha; Westin, Jerker; Dougherty, Mark

2013-01-01

195

Gait Speed and Survival in Older Adults  

PubMed Central

Context Survival estimates help individualize goals of care for geriatric patients, but life tables fail to account for the great variability in survival. Physical performance measures, such as gait speed, might help account for variability, allowing clinicians to make more individualized estimates. Objective To evaluate the relationship between gait speed and survival. Design, Setting, and Participants Pooled analysis of 9 cohort studies (collected between 1986 and 2000), using individual data from 34 485 community-dwelling older adults aged 65 years or older with baseline gait speed data, followed up for 6 to 21 years. Participants were a mean (SD) age of 73.5 (5.9) years; 59.6%, women; and 79.8%, white; and had a mean (SD) gait speed of 0.92 (0.27) m/s. Main Outcome Measures Survival rates and life expectancy. Results There were 17 528 deaths; the overall 5-year survival rate was 84.8% (confidence interval [CI], 79.6%–88.8%)and 10-year survival rate was 59.7% (95%CI, 46.5%–70.6%). Gait speed was associated with survival in all studies (pooled hazard ratio per 0.1 m/s, 0.88; 95% CI, 0.87–0.90; P<. 001). Survival increased across the full range of gait speeds, with significant increments per 0.1 m/s. At age 75, predicted 10-year survival across the range of gait speeds ranged from 19% to 87% in men and from 35% to 91% in women. Predicted survival based on age, sex, and gait speed was as accurate as predicted based on age, sex, use of mobility aids, and self-reported function or as age, sex, chronic conditions, smoking history, blood pressure, body mass index, and hospitalization. Conclusion In this pooled analysis of individual data from 9 selected cohorts, gait speed was associated with survival in older adults.

Studenski, Stephanie; Perera, Subashan; Patel, Kushang; Rosano, Caterina; Faulkner, Kimberly; Inzitari, Marco; Brach, Jennifer; Chandler, Julie; Cawthon, Peggy; Connor, Elizabeth Barrett; Nevitt, Michael; Visser, Marjolein; Kritchevsky, Stephen; Badinelli, Stefania; Harris, Tamara; Newman, Anne B.; Cauley, Jane; Ferrucci, Luigi; Guralnik, Jack

2011-01-01

196

Variations in Kinematics during Clinical Gait Analysis in Stroke Patients  

PubMed Central

In addition to changes in spatio-temporal and kinematic parameters, patients with stroke exhibit fear of falling as well as fatigability during gait. These changes could compromise interpretation of data from gait analysis. The aim of this study was to determine if the gait of hemiplegic patients changes significantly over successive gait trials. Forty two stroke patients and twenty healthy subjects performed 9 gait trials during a gait analysis session. The mean and variability of spatio-temporal and kinematic joint parameters were analyzed during 3 groups of consecutive gait trials (1–3, 4–6 and 7–9). Principal component analysis was used to reduce the number of variables from the joint kinematic waveforms and to identify the parts of the gait cycle which changed during the gait analysis session. The results showed that i) spontaneous gait velocity and the other spatio-temporal parameters significantly increased, and ii) gait variability decreased, over the last 6 gait trials compared to the first 3, for hemiplegic patients but not healthy subjects. Principal component analysis revealed changes in the sagittal waveforms of the hip, knee and ankle for hemiplegic patients after the first 3 gait trials. These results suggest that at the beginning of the gait analysis session, stroke patients exhibited phase of adaptation,characterized by a “cautious gait” but no fatigue was observed.

Boudarham, Julien; Roche, Nicolas; Pradon, Didier; Bonnyaud, Celine; Bensmail, Djamel; Zory, Raphael

2013-01-01

197

A body-worn gait analysis system for evaluating hemiplegic gait.  

PubMed

This paper describes a system for measuring the temporal parameters of hemiplegic gait. This system uses shoe insoles with sensors, acting as switches, placed under the heel, head of the first metatarsal, head of the fifth metatarsal and the big toe. This system is able to monitor gait for up to 10 min and can be used by the patient over any surface. Parameters for evaluating hemiplegic gait are defined, including scuffing during swing and the degree of inversion during stance. PMID:7670701

Granat, M H; Maxwell, D J; Bosch, C J; Ferguson, A C; Lees, K R; Barbenel, J C

1995-07-01

198

Towards Scalable View-Invariant Gait Recognition: Multilinear Analysis for Gait  

Microsoft Academic Search

In this paper we introduce a novel approach for learning view-inva- riant gait representation that does not require synthesizing particular views or any camera calibration. Given walking sequences captured from multiple views for multiple people, we fit a multilinear generative model using higher-order singular value decomposition which decomposes view factors, body configuration factors, and gait-style factors. Gait-style is a view-invariant,

Chan-su Lee; Ahmed M. Elgammal

2005-01-01

199

Complex muscle vibration patterns to induce gait-like lower-limb movements: Proof of concept.  

PubMed

Muscle vibrations can induce motor responses and illusions of complex movements. However, inducing gait-like cyclical movements and illusions requires the application of multiple fast alternating vibrations to lower-limb muscles. The objectives were (1) to test the feasibility of delivering complex vibrations in a time-organized manner and (2) to illustrate the possibility of inducing alternate gait-in-place-like movements using these vibrations. Patterns of vibration, produced by 12 vibrators applied bilaterally on the flexor and extensor muscle groups of the lower limbs, were based on normal gait kinematics. We tested 1 s and 2 s cycle patterns of vibration. Vibrator responses were assessed using auto- and crosscorrelations and frequency analyses based on accelerometry measurements, and compared between patterns. High auto- (>0.8) and crosscorrelation (>0.6) coefficients demonstrated a good response by the vibrators to the control signal. Vibrations induced cyclical, low-amplitude stepping-in-place movements that mimicked alternate walking movements with both legs, with 1 s and 2 s cycle durations, in one nondisabled participant and one participant with American Spinal Injury Association Impairment Scale B spinal cord injury standing, relaxed, with body-weight support. Electromechanical vibrators can deliver complex cyclical vibrations and trigger gait-like lower-limb movements. These results warrant the application of these vibration patterns on individuals with sensorimotor impairments to test their potential in gait rehabilitation. PMID:24933722

Duclos, Cyril; Kemlin, Claire; Lazert, David; Gagnon, Dany; Dyer, Joseph-Omer; Forget, Robert

2014-05-01

200

Dry Friction Bearings.  

National Technical Information Service (NTIS)

Contents: Porous metal ceramic bearings; Mineral ceramic bearings; Self-lubricating pressed wood bearings; Metal materials for special bearings; Operation of rolling surface bearings under dry friction conditions; Rolling surface bearings with solid lubri...

B. D. Voronkov

1970-01-01

201

Weight bearing as a measure of disease progression and efficacy of anti-inflammatory compounds in a model of monosodium iodoacetate-induced osteoarthritis  

Microsoft Academic Search

Objective: To describe an in vivo model in the rat in which change in weight distribution is used as a measure of disease progression and efficacy of acetaminophen and two nonsteroidal anti-inflammatory drugs (NSAIDs) in a model of monosodium iodoacetate (MIA)-induced osteoarthritis (OA).Methods: Intra-articular injections of MIA and saline were administered to male Wistar rats (175–200g) into the right and

S. E Bove; S. L Calcaterra; R. M Brooker; C. M Huber; R. E Guzman; P. L Juneau; D. J Schrier; K. S Kilgore

2003-01-01

202

Gait recognition based on Gabor wavelets and modified gait energy image for human identification  

NASA Astrophysics Data System (ADS)

This paper proposes a method for recognizing human identity using gait features based on Gabor wavelets and modified gait energy images (GEIs). Identity recognition by gait generally involves gait representation, extraction, and classification. In this work, a modified GEI convolved with an ensemble of Gabor wavelets is proposed as a gait feature. Principal component analysis is then used to project the Gabor-wavelet-based gait features into a lower-dimension feature space for subsequent classification. Finally, support vector machine classifiers based on a radial basis function kernel are trained and utilized to recognize human identity. The major contributions of this paper are as follows: (1) the consideration of the shadow effect to yield a more complete segmentation of gait silhouettes; (2) the utilization of motion estimation to track people when walkers overlap; and (3) the derivation of modified GEIs to extract more useful gait information. Extensive performance evaluation shows a great improvement of recognition accuracy due to the use of shadow removal, motion estimation, and gait representation using the modified GEIs and Gabor wavelets.

Huang, Deng-Yuan; Lin, Ta-Wei; Hu, Wu-Chih; Cheng, Chih-Hsiang

2013-10-01

203

Cryogenic Magnetic Bearing Test Facility (CMBTF)  

NASA Technical Reports Server (NTRS)

The Cryogenic Magnetic Bearing Test Facility (CMBTF) was designed and built to evaluate compact, lightweight magnetic bearings for use in the SSME's (space shuttle main engine) liquid oxygen and liquid hydrogen turbopumps. State of the art and tradeoff studies were conducted which indicated that a hybrid permanent magnet bias homopolar magnetic bearing design would be smaller, lighter, and much more efficient than conventional industrial bearings. A test bearing of this type was designed for the test rig for use at both room temperature and cryogenic temperature (-320 F). The bearing was fabricated from state-of-the-art materials and incorporated into the CMBTF. Testing at room temperature was accomplished at Avcon's facility. These preliminary tests indicated that this magnetic bearing is a feasible alternative to older bearing technologies. Analyses showed that the hybrid magnetic bearing is one-third the weight, considerably smaller, and uses less power than previous generations of magnetic bearings.

1992-01-01

204

DYNAMICS OF GAIT IN ACTIVE ELDERLY MEN  

Microsoft Academic Search

The purpose of this study was to identify if, on very active elderly male, the undesirables effects of age in gait dynamic variables where minimized. The gait cycle of 3 healthy and active elderly males (ages: 69.30±1.41 years) and 5 health and active young males (ages: 21.80±0.45 years) was compared in order to verify if the differences (between young and

Filipa João; Vera Moniz Pereira; António Veloso

2007-01-01

205

Toward understanding the limits of gait recognition  

NASA Astrophysics Data System (ADS)

Most state of the art video-based gait recognition algorithms start from binary silhouettes. These silhouettes, defined as foreground regions, are usually detected by background subtraction methods, which results in holes or missed parts due to similarity of foreground and background color, and boundary errors due to video compression artifacts. Errors in low-level representation make it hard to understand the effect of certain conditions, such as surface and time, on gait recognition. In this paper, we present a part-level, manual silhouette database consisting of 71 subjects, over one gait cycle, with differences in surface, shoe-type, carrying condition, and time. We have a total of about 11,000 manual silhouette frames. The purpose of this manual silhouette database is twofold. First, this is a resource that we make available at http://www.GaitChallenge.org for use by the gait community to test and design better silhouette detection algorithms. These silhouettes can also be used to learn gait dynamics. Second, using the baseline gait recognition algorithm, which was specified along with the HumanID Gait Challenge problem, we show that performance from manual silhouettes is similar and only sometimes better than that from automated silhouettes detected by statistical background subtraction. Low performances when comparing sequences with differences in walking surfaces and time-variation are not fully explained by silhouette quality. We also study the recognition power in each body part and show that recognition based on just the legs is equal to that from the whole silhouette. There is also significant recognition power in the head and torso shape.

Liu, Zongyi; Malave, Laura; Osuntogun, Adebola; Sudhakar, Preksha; Sarkar, Sudeep

2004-08-01

206

Automated event detection algorithms in pathological gait.  

PubMed

Accurate automated event detection is important in increasing the efficiency and utility of instrumented gait analysis. Published automated event detection algorithms, however, have had limited testing on pathological populations, particularly those where force measurements are not available or reliable. In this study we first postulated robust definitions of gait events that were subsequently used to compare kinematic based event detection algorithms across difficult pathologies. We hypothesized that algorithm accuracy would vary by gait pattern, and that accurate event detection could be accomplished by first visually classifying the gait pattern, and subsequently choosing the most appropriate algorithm. Nine published kinematic event detection algorithms were applied to an existing instrumented pediatric gait database (primarily cerebral palsy pathologies), that were categorized into 4 visually distinct gait patterns. More than 750 total events were manually rated and these events were used as a gold standard for comparison to each algorithm. Results suggested that for foot strike events, algorithm choice was dependent on whether the foot's motion in terminal swing was more horizontal or vertical. For horizontal foot motion in swing, algorithms that used horizontal position, resultant sagittal plane velocity, or horizontal acceleration signals were most robust; while for vertical foot motion, resultant sagittal velocity or vertical acceleration excelled. For toe off events, horizontal position or resultant sagittal plane velocity performed the best across all groups. We also tuned the resultant sagittal plane velocity signal to walking speed to create an algorithm that can be used for all groups and in real time. PMID:24041468

Bruening, Dustin A; Ridge, Sarah Trager

2014-01-01

207

Agency, gait and self-consciousness.  

PubMed

Agency is an important aspect of bodily self-consciousness, allowing us to separate own movements from those induced by the environment and to distinguish own movements from those of other agents. Unsurprisingly, theoretical frameworks for agency such as central monitoring are closely tied to computational models of sensorimotor control. Until recently agency research has largely focussed on goal-directed movements of the upper limbs. In particular, the influence of performance-related sensory cues and the relevance of prediction signals for agency judgements have been studied through a variety of spatio-temporal mismatches between movement and the sensory consequences of movement. However, agents often perform a different type of movement; highly automated movements that involve the entire body such as walking, cycling, and swimming with potentially different agency mechanisms. Here, we review recent work about agency for full-body movements such as gait, highlighting the effects of performance-related visual and auditory cues on gait agency. Gait movements differ from upper limb actions. Gait is cyclic, more rarely immediately goal-directed, and is generally considered one of the most automatic and unconscious actions. We discuss such movement differences with respect to the functional mechanisms of full-body agency and body-part agency by linking these gait agency paradigms to computational models of motor control. This is followed by a selective review of gait control, locomotion, and models of motor control relying on prediction signals and underlining their relevance for full-body agency. PMID:22226801

Kannape, O A; Blanke, O

2012-02-01

208

PAGAS: Portable and Accurate Gait Analysis System.  

PubMed

Gait analysis systems are powerful tools in the monitoring and rehabilitation of many health conditions which result in an altered gait (such as Parkinson's disease and rheumatoid arthritis), along with the injury of lower limbs. However, current systems that provide accurate gait monitoring and analysis are large and expensive, and therefore are available only in professional settings. The goal of this research is to develop and test a Portable and Accurate Gait Analysis System, denoted PAGAS, which enables patients to monitor their own gait and track their progress and improvement over time. Moreover, PAGAS will enable therapists to follow the progress of their patients over time without the need for multiple visits required at a rehabilitation facility, thus saving significant healthcare costs. PAGAS includes footswitches and a micro-controller, which connects to an Android Smart-phone using Bluetooth communication. An application on the Smartphone analyzes the raw data to produce temporal gait parameters that are displayed to the user on a graphical user interface. PMID:23365885

Wagner, Rojay; Ganz, Aura

2012-01-01

209

Objective clinical evaluation of function. Gait analysis.  

PubMed

Automated gait analysis allows us to document and quantify objectively normal gait, functional deficits, and patient response to therapeutic intervention. Instrumentation for this analysis at the Mayo Clinic Gait Laboratory includes three-dimensional electrogoniometers for measurement of relative joint rotation at the hip, knee, and ankle; footswitches that record foot-floor contact sequences; instrumented mats that measure step length and width; piezoelectric force plates for measurement of floor reaction forces; and two walkways that simulate a variety of ground conditions. We use a DEC-PDP 11/34 computer for acquisition, storage, and analysis of data and for generation of a gait report form that displays a patient's results relative to normal and previous evaluations. Applications of these techniques include assessment of function preoperative and postoperative total joint arthroplasty, quantification of gait faults, and documentation of effectiveness of exercise and gait training techniques. We have demonstrated the reliability of the techniques, accumulated a sizeable normal data bank, and developed a concise, effective data summary for communication with referring practitioners. PMID:6548815

Laughman, R K; Askew, L J; Bleimeyer, R R; Chao, E Y

1984-12-01

210

Bobbie Bear  

NSDL National Science Digital Library

Using a virtual manipulative, children construct combinations of different colored shirts and pants to help Bobbie Bear, who is planning a vacation and wants to know how many different outfits he will be able to make from these combinations.

Mathematics, Illuminations N.

2009-03-06

211

Symmetrical gaits of Cebus apella: implications for the functional significance of diagonal sequence gait in primates  

Microsoft Academic Search

Quadrupedal locomotion of primates is distinguished from the quadrupedalism of many other mammals by several features, including a diagonal sequence (DS) footfall used in symmetrical gaits. This presumably unique feature of primate locomotion has been attributed to an ancestral adaptation for cautious arboreal quadrupedalism on thin, flexible branches. However, the functional significance of DS gait remains largely hypothetical. The study

Ian J. Wallace; Brigitte Demes

2008-01-01

212

Is Freezing of Gait in Parkinson's Disease a Result of Multiple Gait Impairments? Implications for Treatment  

PubMed Central

Several gait impairments have been associated with freezing of gait (FOG) in patients with Parkinson's disease (PD). These include deteriorations in rhythm control, gait symmetry, bilateral coordination of gait, dynamic postural control and step scaling. We suggest that these seemingly independent gait features may have mutual interactions which, during certain circumstances, jointly drive the predisposed locomotion system into a FOG episode. This new theoretical framework is illustrated by the evaluation of the potential relationships between the so-called “sequence effect”, that is, impairments in step scaling, and gait asymmetry just prior to FOG. We further discuss what factors influence gait control to maintain functional gait. “Triggers”, for example, such as attention shifts or trajectory transitions, may precede FOG. We propose distinct categories of interventions and describe examples of existing work that support this idea: (a) interventions which aim to maintain a good level of locomotion control especially with respect to aspects related to FOG; (b) those that aim at avoiding FOG “triggers”; and (c) those that merely aim to escape from FOG once it occurs. The proposed theoretical framework sets the stage for testable hypotheses regarding the mechanisms that lead to FOG and may also lead to new treatment ideas.

Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M.

2012-01-01

213

Effects of Spaceflight and Hindlimb Suspension on the Posture and Gait of Rats  

NASA Technical Reports Server (NTRS)

Instability of posture and gait in astronauts following spaceflight (SF) is thought to result from muscle atrophy and from changes in sensory-motor integration in the CNS (central nervous system) that occur during adaptation to microgravity (micro-G). Individuals are thought to have developed, during SF, adaptive changes for the processing of proprioceptive, vestibular and visual sensory inputs with reduced weighting of gravity-based signals and increased weighting of visual and tactile cues. This sensory-motor rearrangement in the CNS apparently occurs to optimize neuromuscular system function for effective movement and postural control in micro-G. However, these adaptive changes are inappropriate for the 1 g environment and lead to disruptions in posture and gait on return to Earth. Few reports are available on the effects of SF on the motor behavior of animals. Rats studied following 18.5 - 19.5 days of SF in the COSMOS program were described as being ..'inert, apathetic, slow'.. and generally unstable. The hindlimbs of these rats were ..'thrust out from the body with fingers pulled apart and the shin unnaturally pronated'. On the 6th postflight day motor behavior was described as similar to that observed in preflight observations. Improved understanding of the mechanisms leading to these changes can be obtained in animal models through detailed analysis of neural and molecular mechanisms related to gait. To begin this process the posture and gait of rats were examined following exposure to either SF or hindlimb suspension (HLS), and during recovery from these conditions.

Fox, R. A.; Corcoran, M.; Daunton, N. G.; Morey-Holton, E.

1994-01-01

214

Unstable gait due to spasticity of the rectus femoris: gait analysis and motor nerve block.  

PubMed

We present the case of a 54 year-old man presenting with a right Brown-Séquard plus syndrome (BSPS) after a traumatic cervical spinal cord injury. After being operated on with selective tibial neurotomy and triceps surae lengthening because of a right spastic equinus foot, he developed a gait disorder at high speed. The patient complained about an instability of the right knee. Observational gait analysis exhibited an oscillating, flexion/extension motion of the right knee during stance, which was confirmed by gait analysis. Dynamic electromyographic recordings exhibited a clonus of the right rectus femoris (RF) during stance. The spastic activity of the RF and the abnormal knee motion totally reversed after a motor nerve block of the RF, as well as after botulinum toxin type A injection into the RF. We emphasize that complex, spastic gait disorders can benefit from a comprehensive assessment including gait analysis and nerve blocks. PMID:23043733

Gross, R; Leboeuf, F; Rémy-Néris, O; Perrouin-Verbe, B

2012-12-01

215

Dynamic stability and phase resetting during biped gait  

NASA Astrophysics Data System (ADS)

Dynamic stability during periodic biped gait in humans and in a humanoid robot is considered. Here gait systems of human neuromusculoskeletal system and a humanoid are simply modeled while keeping their mechanical properties plausible. We prescribe periodic gait trajectories in terms of joint angles of the models as a function of time. The equations of motion of the models are then constrained by one of the prescribed gait trajectories to obtain types of periodically forced nonlinear dynamical systems. Simulated gait of the models may or may not fall down during gait, since the constraints are made only for joint angles of limbs but not for the motion of the body trunk. The equations of motion can exhibit a limit cycle solution (or an oscillatory solution that can be considered as a limit cycle practically) for each selected gait trajectory, if an initial condition is set appropriately. We analyze the stability of the limit cycle in terms of Poincaré maps and the basin of attraction of the limit cycle in order to examine how the stability depends on the prescribed trajectory. Moreover, the phase resetting of gait rhythm in response to external force perturbation is modeled. Since we always prescribe a gait trajectory in this study, reacting gait trajectories during the phase resetting are also prescribed. We show that an optimally prescribed reacting gait trajectory with an appropriate amount of the phase resetting can increase the gait stability. Neural mechanisms for generation and modulation of the gait trajectories are discussed.

Nomura, Taishin; Kawa, Kazuyoshi; Suzuki, Yasuyuki; Nakanishi, Masao; Yamasaki, Taiga

2009-06-01

216

Reduction in bearing size due to superconductors in magnetic bearings  

NASA Technical Reports Server (NTRS)

A design concept that reduces the size of magnetic bearings is assessed. The small size will enable magnetic bearings to fit into limited available bearing volume of cryogenic machinery. The design concept, called SUPERC, uses (high Tc) superconductors or high-purity aluminum conductors in windings instead of copper. The relatively high-current density of these conductors reduces the slot radial thickness for windings, which reduces the size of the bearings. MTI developed a sizing program called SUPERC that translates the high-current density of these conductors into smaller sized bearings. This program was used to size a superconducting bearing to carry a 500 lb. load. The sizes of magnetic bearings needed by various design concepts are as follows: SUPERC design concept = 3.75 in.; magnet-bias design concept = 5.25 in.; and all electromagnet design concept = 7.0 in. These results indicate that the SUPERC design concept can significantly reduce the size of the bearing. This reduction, in turn, reduces the weight and yields a lighter bearing. Since the superconductors have inherently near-zero resistance, they are also expected to save power needed for operation considerably.

Rao, Dantam K.; Lewis, Paul; Dill, James F.

1991-01-01

217

White Matter Hyperintensities, Exercise and Improvement in Gait Speed: Does the Type of Gait Rehabilitation Matter?  

PubMed Central

Background and Objectives White matter hyperintensities (WMH) on brain MRI are associated with cognitive and mobility impairment in older adults. We examined whether WMH in tracts in older adults with mobility impairment are linked to outcomes of gait rehabilitation interventions. Design A 12-week randomized controlled single-blind trial. Setting University-based mobility research laboratory. Participants Ambulatory adults aged 65 and older with mobility impairment. Intervention A conventional gait intervention focusing on walking, endurance, balance, and strength (WEBS, n=21) compared to a task-oriented intervention focused on timing and coordination of gait (TC, n=23). Measurements We measured self-paced gait speed over an instrumented walkway, pre and post intervention, and quantified WMH and brain volumes on pre-intervention brain MRI using an automated segmentation process. We overlaid a white matter tract atlas on the segmented images to measure tract WMH volumes and normalized WMH volumes to total brain volume. Aggregate WMH volumes in all white matter tracts and individual WMH volumes in specific longitudinal tracts (the superior longitudinal fasciculus, inferior longitudinal fasciculus and the fronto-occipital fasciculus) and cingulum were obtained. Results Gait speed gains in the TC group were of the same magnitude, independent of the WMH volume measures in all except the cingulum. However, in the WEBS group, gain in gait speed was smaller with greater overall tract WMH volumes (P<0.001) and with greater WMH volume in the three longitudinal tracts (P< 0.001 to 0.025). Conclusion Gains in gait speed with two types of gait rehabilitation are associated with individual differences in WMH. Task-oriented therapy that targets timing and coordination of gait may particularly benefit older adults with WMH in brain tracts that influence gait and cognition.

Nadkarni, Neelesh K.; Studenski, Stephanie A.; Perera, Subashan; Rosano, Caterina; Aizenstein, Howard J.; Brach, Jennifer S.; VanSwearingen, Jessie M.

2013-01-01

218

Gait Initiation in Children with Rett Syndrome  

PubMed Central

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait.

Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L.; Frigo, Carlo Albino; Cavallari, Paolo

2014-01-01

219

Gait initiation in children with rett syndrome.  

PubMed

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L; Frigo, Carlo Albino; Cavallari, Paolo

2014-01-01

220

Gait synchronization in Caenorhabditis elegans.  

PubMed

Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

Yuan, Jinzhou; Raizen, David M; Bau, Haim H

2014-05-13

221

A historical review of gait analysis.  

PubMed

Healthcare professionals have long been concerned with the assessment of human gait, but only recently were they able to utilize instrumental gait analysis in routine clinical practice for diagnosis, and to guide the selection of treatment methods for complex musculo-skeletal and neurological disorders. The development of motion analysis systems has progressed through several stages from simple to more sophisticated, versatile, multimodal, and accurate equipment. Several computerized motion analysis systems are now commercially available for the measurement of human gait. These vary in their design and performance. The purpose of this review is to summarize briefly the history and advances in the technology of instrumental gait analysis, especially during the past 3 decades. Further, it is hoped that this review will give clinical practitioners and researchers a general insight into the variety of measurement systems that are currently available for gait analysis and enable them to make an informed choice of the motion analysis system that best suits their clinical needs. PMID:21063300

Al-Zahrani, Khaled S; Bakheit, Magid O

2008-04-01

222

Recognition of affect based on gait patterns.  

PubMed

To provide a means for recognition of affect from a distance, this paper analyzes the capability of gait to reveal a person's affective state. We address interindividual versus person-dependent recognition, recognition based on discrete affective states versus recognition based on affective dimensions, and efficient feature extraction with respect to affect. Principal component analysis (PCA), kernel PCA, linear discriminant analysis, and general discriminant analysis are compared to either reduce temporal information in gait or extract relevant features for classification. Although expression of affect in gait is covered by the primary task of locomotion, person-dependent recognition of motion capture data reaches 95% accuracy based on the observation of a single stride. In particular, different levels of arousal and dominance are suitable for being recognized in gait. It is concluded that gait can be used as an additional modality for the recognition of affect. Application scenarios include monitoring in high-security areas, human-robot interaction, and cognitive home environments. PMID:20350859

Karg, Michelle; Kühnlenz, Kolja; Buss, Martin

2010-08-01

223

Gait stability in children with cerebral palsy  

PubMed Central

Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE’s sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (~1.5 cm), while effects of walking speed (~20 cm per m/s increase in walking speed) and group (~5cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP.

Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

2013-01-01

224

Development and Decline of Upright Gait Stability  

PubMed Central

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers.

Iosa, Marco; Fusco, Augusto; Morone, Giovanni; Paolucci, Stefano

2014-01-01

225

The asymmetric gait toenail unit sign.  

PubMed

The aim of this investigation was to resolve a diagnostic problem and report toenail unit changes attributable to shoe friction that resemble onychomycosis, but that are fungus-negative, and identify common skeletal causes in patients with an asymmetric walking gait. X-ray and clinical feet inspections were performed to evaluate skeletal components that change normal foot biodynamics. Forty-nine patients, all dermatophyte-negative, were reviewed. All patients were those seen in our private practice who demonstrated skeletal and toenail unit abnormalities such as onycholysis, nail bed keratosis resembling distal subungual onychomycosis, nail plate surface abnormalities, distal toe skin keratosis, a diagnostic nail plate shape, as well as several skeletal abnormalities. The clinical abnormalities of the asymmetric gait syndrome include onycholysis, nail bed keratosis, nail plate surface abnormalities, and a diagnostic nail plate shape. By the patient's history, the skeletal findings that were present worsened with age and, in many patients, they were familial. Onychomycosis does not lead to an asymmetric gait nail problem, asymmetric gait toenail does not favor dermatophyte infection, and not all nail dystrophies are the result of an asymmetric walking gait. PMID:23008938

Zaias, Nardo; Rebell, Gerbert; Casal, German; Appel, Jason

2012-01-01

226

MFC histogram and Poincare plot images for automated gait detection  

Microsoft Academic Search

In this paper, we apply support vector machines (SVMs) for the automatic recognition of young-old gait from their respective gait-patterns. Minimum foot clearance (MFC) data of 30 young and 28 elderly participants were analysed using a PEAK-2D motion analysis system. Gait features extracted from individual MFC histogram-plot and Poincare-plots were used to develop gait classification models using SVMs. Test results

R. Begg; M. Palaniswami; B. Owen; S. Taylor; L. Dell'Oro

2004-01-01

227

Lubrication for high load duplex bearings  

SciTech Connect

Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

Steinhoff, R.G.

1997-08-01

228

Robotic-assessment of walking in individuals with gait disorders.  

PubMed

Walking deficits are a common bi-product of numerous neurological injuries, such as stroke and spinal cord injury. A number of new therapeutic interventions, such as body-weight supported locomotor training and robotic technologies aim to improve walking function and reduce co-morbidities. Currently, there is no way to determine what the optimal set of training parameters are for maximizing step performance. This paper presents a technique for estimating the walking performance of individuals with gait disorders using a robotic-orthosis. The device, called the Lokomat is coupled to the subject through instrumented leg cuffs, while the split-belt treadmill on which the subject walks is instrumented with piezo-electric force sensors allowing for the calculation of ground reaction forces and center of pressure. Using this data, a real-time inverse dynamics approach can be used to estimate the kinetics and kinematics of the subject, and when combined with electromyographic (EMG) data, the set of training conditions through which the subject generates the most appropriate EMG patterns and joint moments can be identified. The proposed technique will for the first time provide clinicians a way of determining the optimal gait training parameters for each individual, and also track their functional recovery throughout their neurorehabilitation program. It is postulated that training at the conditions that maximizes stepping performance will lead to higher gains in over-ground walking ability. PMID:17271392

Hidler, J

2004-01-01

229

Human Odometry Verifies the Symmetry Perspective on Bipedal Gaits  

Microsoft Academic Search

Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results suggest that when distance is measured

M. T. Turvey; Steven J. Harrison; Till D. Frank; Claudia Carello

2012-01-01

230

Animal gait generation based on human feeling for quadrupedal robot  

Microsoft Academic Search

In the field of the pet robot and robot assisted therapy (RAT), the creatural motion is important for the robots imitated the form of various animals. This paper presents the generation method of animal gait for quadrupedal robot. Here, we have employed AIBO as experimental quadrupedal robot and created the gait of AIBO in imitation of animal gait. At first,

Hitoshi Nishi; Hidekazu Suzuki

2008-01-01

231

Gait analysis using accelerometry in dystrophin-deficient dogs  

Microsoft Academic Search

Dogs affected with Golden Retriever Muscular Dystrophy (GRMD) exhibit striking clinical similarities with patients suffering from Duchenne muscular dystrophy (DMD), particularly gait impairments. The purpose of this study was to describe the use and reliability of accelerometry in gait assessment of dogs with muscular dystrophy. Eight healthy and 11 GRMD adult dogs underwent three gait assessment sessions, using accelerometry. Three-axial

Inès Barthélémy; Eric Barrey; Jean-Laurent Thibaud; Ane Uriarte; Thomas Voit; Stéphane Blot; Jean-Yves Hogrel

2009-01-01

232

The effect of trunk flexion on able-bodied gait  

Microsoft Academic Search

This study examined the effect of sagittal trunk posture on the gait of able-bodied subjects. Understanding the effect of trunk posture on gait is of clinical interest since alterations in trunk posture often occur with age or in the presence of spinal pathologies, such as lumbar flatback. Gait analysis was conducted on 14 adults walking at self-selected slow, normal, and

Devjani Saha; Steven Gard; Stefania Fatone

2008-01-01

233

Voluntary gait speed adaptation for robot-assisted treadmill training  

Microsoft Academic Search

Robot-assisted gait training currently lacks the possibility of the robot to automatically adapt to the patient's needs and demands (so called ldquobio-cooperative control strategiesrdquo). It is desired to give the patient voluntary control over training parameters such as gait speed or joint trajectories. We implemented a control algorithm for the driven gait orthosis Lokomat that allows severely disabled stroke patients

Alexander KOENIG; Carmen BINDER; J. v. Zitzewitz; X. Omlin; M. Bolliger; R. Riener

2009-01-01

234

Kinetics of stiff-legged gait: induced acceleration analysis  

Microsoft Academic Search

Treating spastic paretic stiff-legged gait, defined as reduced knee flexion in swing, holds a high priority in the rehabilitation of patients with upper motor neuron lesions. We propose a method to determine the relative contributions of hip, knee, and ankle inpairments to this disability. We analyzed the gait of ten patients with stiff-legged gait (SLG) due to a single stroke

Patrick O. Riley; D. Casey Kerrigan

1999-01-01

235

The evolution of clinical gait analysis part l: kinesiological EMG  

Microsoft Academic Search

Abstract In 1996, I was asked by Roy Davis, President of the Gait and Clinical Movement Analysis Society, to be the presidential guest speaker at the Birmingham, AL, annual society meeting and present a talk on the development of clinical gait analysis. Following my presentation, James Gage, Editor-in-Chief for Gait and Posture, and David Winter, Associate Editor for review articles

David H. Sutherland

2001-01-01

236

EXPLORING OPTIMAL GAITS FOR PLANAR CARANGIFORM ROBOT FISH LOCOMOTION  

Microsoft Academic Search

This paper presents a strategy to flnd an optimal gait for the model of the biomimetic swimmer developed at Caltech to transit forward minimizing control efiort, or the integral of squared angular acceleration of the two joints. According to the previous works, it is accepted that a series of sinusoidal-type gaits generates forward transition. Using this sinusoidal gaits as initial

Keehong Seo; Richard Murray; Jin S. Lee

237

Simulating pathological gait using the enhanced linear inverted pendulum model  

Microsoft Academic Search

In this paper, we propose a new method to simulate human gait motion when muscles are weakened. The method is based on the enhanced version of three-dimensional linear inverted pendulum model that is used for generation of gait in robotics. After the normal gait motion is generated by setting the initial posture and the parameters that decide the trajectories of

Taku Komura; Akinori Nagano; Howard Leung; Yoshihisa Shinagawa

2005-01-01

238

Bear Bones  

NSDL National Science Digital Library

An estimated ten million Americans have osteoporosis, an age-related disease in which the bones gradually become brittle and weak. Now, scientists are looking to animals for clues on how to combat this condition. This resource describes the study of sustaining bone strength of hibernating bears.

Science Update;

2004-03-08

239

Virtual gait training for children with cerebral palsy using the Lokomat gait orthosis.  

PubMed

The Lokomat gait orthosis was developed in the Spinal Cord Injury Center at the University Hospital Balgrist Zurich and provides automatic gait training for patients with neurological gait impairments, such as Cerebral Palsy (CP). Each patient undergoes a task-oriented Lokomat rehabilitation training program via a virtual reality setup. In four virtual scenarios, the patient is able to exercise tasks such as wading through water, playing soccer, overstepping obstacles or training in a street scenario, each task offering varying levels of difficulty. Patients provided positive feedback in reference to the utilized haptic method, specifically addressing the sufficient degree of realism. In a single case study, we verified the task difficulty. PMID:18391287

Koenig, Alexander; Wellner, Mathias; Köneke, Susan; Meyer-Heim, Andreas; Lünenburger, Lars; Riener, Robert

2008-01-01

240

Motor imagery of gait: a quantitative approach.  

PubMed

Motor imagery (MI) is widely used to study cognitive aspects of the neural control of action. Prior studies were mostly centred on hand and arm movements. Recently a few studies have used imagery tasks to explore the neurophysiology of human gait, but it remains unclear how to ascertain whether subjects actually perform imagery of gait as requested. Here we describe a new experimental protocol to quantify imagery of gait, by behaviourally distinguishing it from visual imagery (VI) processes and by showing its temporal correspondence with actual gait. Fourteen young healthy subjects performed two imagery tasks and an actual walking (AW) task. During both imagery tasks subjects were sitting on a chair and faced a computer screen that presented photographs of walking trajectories. During one task (MI), subjects had to imagine walking along the walking trajectory. During the other task (VI), subjects had to imagine seeing a disc moving along the walking trajectory. During the AW task, subjects had to physically walk along the same walking trajectory as presented on the photographs during the imagery tasks. We manipulated movement distance by changing the length of the walking trajectory, and movement difficulty by changing the width of the walking trajectory. Subjects reported onset and offset of both actual and imagined movements with a button press. The time between the two button presses was taken as the imagined or actual movement time (MT). MT increased with increasing path length and decreasing path width in all three tasks. Crucially, the effect of path width on MT was significantly stronger during MI and AW than during VI. The results demonstrate a high temporal correspondence between imagined and AW, suggesting that MI taps into similar cerebral resources as those used during actual gait. These results open the possibility of using this protocol for exploring neurophysiological correlates of gait control in humans. PMID:17211663

Bakker, M; de Lange, F P; Stevens, J A; Toni, I; Bloem, B R

2007-05-01

241

An investigation of gait in children with Attention Deficit Hyperactivity Disorder: A case controlled study.  

PubMed

This study aimed to compare the gait of children with ADHD - Combined Type (ADHD-CT) to typically developing (TD) children. Children with ADHD-CT (n=14; mean age 10 years 4 months) and a TD group (n=13; mean age 10 years 9 months) walked at self-selected slow, preferred and fast speed on an electronic walkway system. Participants completed a total of 15 walking trials; 5 trials per walking condition. Groups were matched on age, intellectual functioning, height and weight. In the preferred walking condition, there was no difference in spatio-temporal gait variables between the ADHD-CT and TD control groups. At self-selected fast speed, children with ADHD-CT were faster and walked with a higher cadence. The subtle alterations in gait pattern that may reflect a timing deficit is consistent with previous ADHD motor studies. In addition, this study extends previous studies in characterising the unique gait profile of non-medicated children with ADHD-CT where a diagnosis of autism spectrum disorder has been ruled out. PMID:24837426

Papadopoulos, Nicole; McGinley, Jennifer L; Bradshaw, John L; Rinehart, Nicole J

2014-08-30

242

Analysis of Human Gait Radar Signal Using Reassigned WVD  

NASA Astrophysics Data System (ADS)

Human gait is one of the biological features for human recognition. The key feature of gait can be acquired by analyzing the human echo signal to CW radar. Based on the data from the test CW gait radar, the methods for analyzing multi-component non-stationary signal are discussed in detail. The comparison among the application STFT, WVD, Pseudo-smoothed WVD and its improvements in gait signal are given, and the basic method for gait feature extraction based on time-frequency analysis is proposed. The results in this paper will be a well support for further research.

Zhang, Jun

243

19 CFR 10.98 - Copper-bearing fluxing material.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Copper-bearing fluxing material. 10.98...Provisions Fluxing Material § 10.98 Copper-bearing fluxing material. ...contain by weight not over 15 percent copper. (b) [Reserved] (c)...

2013-04-01

244

Gait identification from invisible shadows  

NASA Astrophysics Data System (ADS)

This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which identification of the subject followed. The experiments using the database show the effectiveness of the proposed method and further prove the superiority of using multiple viewpoints compared to a single viewpoint.

Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

2012-05-01

245

A switching formula for optimal gait transitions  

Microsoft Academic Search

This paper proposes a simple, closed-form switching formula for determining the optimal gait transition speeds of legged robots. For robots with even-numbered legs that are arranged symmetrically along the direction of locomotion, the formula determines the forward locomotion speed at which running (gallop) becomes more efficient than walking (trot). The accuracy of the switching formula is empirically evaluated through a

Hyuk Kang; Byungchul An; F. C. Park

2010-01-01

246

Some Properties of Regularly Realizable Gait Matrices.  

National Technical Information Service (NTIS)

While the number of theoretically possible gaits for animals or legged vehicles is very large, only a few of these are actually employed in natural legged locomotion. The paper presents a condition, called regular realizability, which is advanced as an ex...

A. K. Jain R. B. McGhee

1972-01-01

247

Kinematic Gait Analysis in Equine Carpal Lameness  

Microsoft Academic Search

Gait analysis plays a major role in the clinical evaluation of equine lameness. It is generally accepted that the clinician expresses the grade of lameness as a subjective score. In this study lameness was objectively assessed using a standardized transient lameness model, in which lameness was induced by intra-articular injection of bacterial endotoxin into the radiocarpal joint of ponies. Lameness

W. Back; A. Barneveld; P. R. Van Weeren; A. J. Van den Bogert

1993-01-01

248

A practical gait analysis system using gyroscopes  

Microsoft Academic Search

This study investigated the possibility of using uni-axial gyroscopes to develop a simple portable gait analysis system. Gyroscopes were attached on the skin surface of the shank and thigh segments and the angular velocity for each segment was recorded in each segment. Segment inclinations and knee angle were derived from segment angular velocities. The angular signals from a motion analysis

Kaiyu Tong; Malcolm H Granat

1999-01-01

249

Improved Gait Classification with Different Smoothing Techniques  

Microsoft Academic Search

Gait as a biometric has received great attention nowadays as it can offer human identification at a distance without any contact with the feature capturing device. This is motivated by the increasing number of synchronised closed-circuit television (CCTV) cameras which have been installed in many major towns, in order to monitor and prevent crime by identifying the criminal or suspect.

Hu Ng; Hau-Lee Tong; Wooi Haw Tan; Junaidi Abdullah

2011-01-01

250

Gait classification with different covariate factors  

Microsoft Academic Search

Gait as a biometric has received great attention nowadays as it can offer human identification at a distance without any contact with the feature capturing device. This is motivated by the increasing number of synchronised closed-circuit television (CCTV) cameras which have been installed in many major towns, in order to monitor and prevent crime. This paper proposes a new approach

Hu Ng; Hau-Lee Tong; Wooi-Haw Tan; Tzen-Vun Yap; Junaidi Abdullah

2010-01-01

251

Comparison of Gait Aspects According to FES Stimulation Position Applied to Stroke Patients  

PubMed Central

[Purpose] This study sought to identify the gait aspects according to the FES stimulation position in stroke patients during gait training. [Subjects and Methods] To perform gait analysis, ten stroke patients were grouped based on 4 types of gait conditions: gait without FES stimulation (non-FES), gait with FES stimulation on the tibialis anterior (Ta), gait with FES stimulation on the tibialis anterior and quadriceps (TaQ), and gait with FES stimulation on the tibialis anterior and gluteus medius (TaGm). [Results] Based on repeated measures analysis of variance of measurements of gait aspects comprised of gait speed, gait cycle, and step length according to the FES stimulation position, the FES stimulation significantly affected gait aspects. [Conclusion] In conclusion, stimulating the tibialis anterior and quadriceps and stimulating the tibialis anterior and gluteus medius are much more effective than stimulating only the tibialis anterior during gait training in stroke patients using FES.

Mun, Byeong-mu; Kim, Tae-ho; Lee, Jin-hwan; Lim, Jin-youg; Seo, Dong-kwon; Lee, Dong-jin

2014-01-01

252

Gait recognition based on Kinect sensor  

NASA Astrophysics Data System (ADS)

This paper presents gait recognition based on human skeleton and trajectory of joint points captured by Microsoft Kinect sensor. In this paper Two sets of dynamic features are extracted during one gait cycle: the first is Horizontal Distance Features (HDF) that is based on the distances between (Ankles, knees, hands, shoulders), the second set is the Vertical Distance Features (VDF) that provide significant information of human gait extracted from the height to the ground of (hand, shoulder, and ankles) during one gait cycle. Extracting these two sets of feature are difficult and not accurate based on using traditional camera, therefore the Kinect sensor is used in this paper to determine the precise measurements. The two sets of feature are separately tested and then fused to create one feature vector. A database has been created in house to perform our experiments. This database consists of sixteen males and four females. For each individual, 10 videos have been recorded, each record includes in average two gait cycles. The Kinect sensor is used here to extract all the skeleton points, and these points are used to build up the feature vectors mentioned above. K-nearest neighbor is used as the classification method based on Cityblock distance function. Based on the experimental result the proposed method provides 56% as a recognition rate using HDF, while VDF provided 83.5% recognition accuracy. When fusing both of the HDF and VDF as one feature vector, the recognition rate increased to 92%, the experimental result shows that our method provides significant result compared to the existence methods.

Ahmed, Mohammed; Al-Jawad, Naseer; Sabir, Azhin T.

2014-05-01

253

Treadmill training with partial body weight support after stroke: a review.  

PubMed

Restoration and improvement of gait after stroke are major aspects of neurorehabilitation. Mobilization out of the bed into the wheelchair and verticalisation with the help of a standing frame are first steps. With the patient cardiovascular stable, gait restoration is put on the agenda. Instead of tone-inhibiting and gait preparatory maneuvers, patients should practice complex gait cycles repetitively. Treadmill training with partial body weight support enables the harness-secured patients to practice numerous steps assisted by two or three therapists. In controlled studies, it proved equally effective as walking on the floor. Gait machines, as the Lokomat or the Gait Trainer GTI, intend to relieve the strenuous effort for the therapists. For the GTI, several controlled trials showed a superior effect in acute stroke patients with respect to walking ability and velocity. For the ambulatory patient, aerobic treadmill training is effective to improve speed and endurance without worsening gait quality. Belt velocity and inclination are gradually increased so that the patients reach a predefined target heart rate. On the belt, patients walk more symmetrically, and higher velocities result in a facilitation of paretic muscles and render gait more efficient. In summary, gait rehabilitation has seen dramatic changes over the last years. More is to be expected. PMID:18356589

Hesse, Stefan

2008-01-01

254

Moving forward on gait measurement: toward a more refined approach.  

PubMed

Gait is emerging as a powerful measurement tool in neurodegenerative disorders to identify markers of incipient pathology, inform diagnostic algorithms and disease progression, and measure the efficacy of interventions. However, it is unclear which of the many gait outcomes is most appropriate for each of these purposes. In this review, we summarise key topics relating to gait measurement. We draw on literature from Parkinson's disease, ageing, and neurodegenerative disease to address the issue of variable selection with the goal of moving toward a structured approach to measurement. Findings from this review identify a wide range of spatiotemporal and dynamic characteristics; however, their suitability differs according to the aim of measurement. Gait speed is useful as a global characteristic of performance but may not capture the nature of underlying pathology. Inconsistent application, reporting, and interpretation of gait outcomes currently preclude a prescriptive approach. Conceptual models of gait may facilitate a reasoned approach to outcome selection. We also recommend harmonisation of protocols, longitudinal cohort studies, and use of novel technologies and methods of analysis to provide a complete picture of gait. Gait characteristics are "fit for purpose" when selected according to a clear rationale and in accordance with their clinimetric properties. Evidence supports the use of gait as a biomarker of disease and to complement diagnosis and inform disease management. A structured approach to measurement is urgently required to fully realise the contribution gait can make to our understanding of neurodegenerative disease. PMID:24132841

Lord, Sue; Galna, Brook; Rochester, Lynn

2013-09-15

255

Real-time gait event detection for paraplegic FES walking.  

PubMed

A real-time method for the detection of gait events that occur during the electrically stimulated locomotion of paraplegic subjects is described. It consists of a two-level algorithm for the processing of sensor signals and the determination of gait event times. Sensor signals and information about the progression of the stimulator though its pre-specified stimulation "pattern" are processed by a machine intelligence (fuzzy logic) algorithm to determine an initial estimate of the patient's current phase of gait. This is then reviewed and modified by a second algorithm that removes spurious gait estimates, and determines gait event times. These gait event times are known to the system within approximately one-half of a gait cycle. The resulting gait event detection system was successfully evaluated on three subjects. Detection accuracy is not adversely affected by day-to-day gait variability. This work resolved technical and practical issues that previously limited the real time application of these methods. In particular, cosmetically acceptable insole force transducers were used. This gait event detector is designed for use in a real time controller for the automatic adjustment of the intensity and timing of stimulation while the subject is walking using functional electrical stimulation (FES). PMID:11482364

Skelly, M M; Chizeck, H J

2001-03-01

256

Gait and upper limb variability in Parkinson's disease patients with and without freezing of gait.  

PubMed

Patients with Parkinson's disease (PD) and freezing of gait (FOG) (freezers) demonstrate high gait variability. The objective of this study was to determine whether freezers display a higher variability of upper limb movements and elucidate if these changes correlate with gait. We were the first group to compare directly objectively measured gait and upper limb movement variability of freezers between freezing episodes. Patients with objectively verified FOG (n = 11) and PD patients without FOG (non-freezers) (n = 11) in a non-randomized medication condition (OFF/ON) were analyzed. Uncued antiphasic finger tapping and forearm diadochokinetic movements were analyzed via three-dimensional ultrasound kinematic measurements. Gait variability of straight gait was assessed using ground reaction forces. Freezers had shorter stride length (p = 0.004) and higher stride length variability (p = 0.005) in the medication OFF condition. Movement variability was not different during finger tapping or diadochokinesia between the groups. There was a trend towards more freezing of the upper limb during finger tapping for the freezers (p = 0.07). Variability in stride length generation and stride timing was not associated with variability of upper limb movement in freezers. Our findings demonstrate that: (1) freezers have a higher spatial gait variability between freezing episodes; (2) freezing-like episodes of the upper limb occur in PD patients, and tend to be more pronounced among freezers than non-freezers for finger tapping; (3) spatial and temporal upper extremity variability is equally affected in freezers and non-freezers in an uncued task. Upper limb freezing is not correlated to lower limb freezing, implicating a different pathophysiology. PMID:24305993

Barbe, Michael T; Amarell, Martin; Snijders, Anke H; Florin, Esther; Quatuor, Eva-Lotte; Schönau, Eckhard; Fink, Gereon R; Bloem, Bastiaan R; Timmermann, Lars

2014-02-01

257

Kinematic Analysis Quantifies Gait Abnormalities Associated with Lameness in Broiler Chickens and Identifies Evolutionary Gait Differences  

PubMed Central

This is the first time that gait characteristics of broiler (meat) chickens have been compared with their progenitor, jungle fowl, and the first kinematic study to report a link between broiler gait parameters and defined lameness scores. A commercial motion-capturing system recorded three-dimensional temporospatial information during walking. The hypothesis was that the gait characteristics of non-lame broilers (n?=?10) would be intermediate to those of lame broilers (n?=?12) and jungle fowl (n?=?10, tested at two ages: immature and adult). Data analysed using multi-level models, to define an extensive range of baseline gait parameters, revealed inter-group similarities and differences. Natural selection is likely to have made jungle fowl walking gait highly efficient. Modern broiler chickens possess an unbalanced body conformation due to intense genetic selection for additional breast muscle (pectoral hypertrophy) and whole body mass. Together with rapid growth, this promotes compensatory gait adaptations to minimise energy expenditure and triggers high lameness prevalence within commercial flocks; lameness creating further disruption to the gait cycle and being an important welfare issue. Clear differences were observed between the two lines (short stance phase, little double-support, low leg lift, and little back displacement in adult jungle fowl; much double-support, high leg lift, and substantial vertical back movement in sound broilers) presumably related to mass and body conformation. Similarities included stride length and duration. Additional modifications were also identified in lame broilers (short stride length and duration, substantial lateral back movement, reduced velocity) presumably linked to musculo-skeletal abnormalities. Reduced walking velocity suggests an attempt to minimise skeletal stress and/or discomfort, while a shorter stride length and time, together with longer stance and double-support phases, are associated with instability. We envisage a key future role for this highly quantitative methodology in pain assessment (associated with broiler lameness) including experimental examination of therapeutic agent efficacy.

Caplen, Gina; Hothersall, Becky; Murrell, Joanna C.; Nicol, Christine J.; Waterman-Pearson, Avril E.; Weeks, Claire A.; Colborne, G. Robert

2012-01-01

258

The effect of kinematic and kinetic changes on meniscal strains during gait.  

PubMed

The menisci play an important role in load distribution, load bearing, joint stability, lubrication, and proprioception. Partial meniscectomy has been shown to result in changes in the kinematics and kinetics at the knee during gait that can lead to progressive meniscal degeneration. This study examined changes in the strains within the menisci associated with kinematic and kinetic changes during the gait cycle. The gait changes considered were a 5 deg shift toward external rotation of the tibia with respect to the femur and an increased medial-lateral load ratio representing an increased adduction moment. A finite element model of the knee was developed and tested using a cadaveric specimen. The cadaver was placed in positions representing heel-strike and midstance of the normal gait, and magnetic resonance images were taken. Comparisons of the model predictions to boundaries digitized from images acquired in the loaded states were within the errors produced by a 1 pixel shift of either meniscus. The finite element model predicted that an increased adduction moment caused increased strains of both the anterior and posterior horns of the medial meniscus. The lateral meniscus exhibited much lower strains and had minimal changes under the various loading conditions. The external tibial rotational change resulted in a 20% decrease in the strains in the posterior medial horn and increased strains in the anterior medial horn. The results of this study suggest that the shift toward external tibial rotation seen clinically after partial medial meniscectomy is not likely to cause subsequent degenerative medial meniscal damage, but the consequence of this kinematic shift on the pathogenesis of osteoarthritis following meniscectomy requires further consideration. PMID:21186896

Netravali, Nathan A; Koo, Seungbum; Giori, Nicholas J; Andriacchi, Thomas P

2011-01-01

259

Modeling effects of sagittal-plane hip joint stiffness on reciprocating gait orthosis-assisted gait.  

PubMed

Upright ambulation is believed to improve quality of life for persons with lower-limb paralysis (LLP). However, ambulatory orthoses for persons with LLP, like reciprocating gait orthoses (RGOs), result in a slow, exhausting gait. Increasing the hip joint stiffness of these devices may improve the efficiency of RGO-assisted gait. The small, diverse population of RGO users makes subject recruitment challenging for clinical investigations. Therefore, we developed a lower-limb paralysis simulator (LLPS) that enabled nondisabled persons to exhibit characteristics of RGO-assisted gait, thereby serving as surrogate models for research. For this study, tests were conducted to determine the effects of increased hip joint stiffness on gait of nondisabled persons walking with the LLPS. A motion capture system, force plates, and spirometer were used to measure the hip flexion, crutch ground reaction forces (GRFs), and oxygen consumption of subjects as they walked with four different hip joint stiffness settings. Increasing the hip joint stiffness decreased hip flexion during ambulation but did not appear to affect the crutch GRFs. Walking speed was observed to initially increase with increases in hip joint stiffness, and then decrease. These findings suggest that increasing hip joint stiffness may increase walking speed for RGO users. PMID:24699979

Johnson, William Brett; Fatone, Stefania; Gard, Steven A

2014-02-01

260

The golden ratio of gait harmony: repetitive proportions of repetitive gait phases.  

PubMed

In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number ? known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with ?, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from ? (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait. PMID:23862161

Iosa, Marco; Fusco, Augusto; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

2013-01-01

261

Unicompartmental Knee Arthroplasty Enables Near Normal Gait at Higher Speeds, Unlike Total Knee Arthroplasty  

PubMed Central

Top walking speed (TWS) was used to compare UKA with TKA. Two groups of 23 patients, well matched for age, gender, height and weight and radiological severity were recruited based on high functional scores, more than twelve months post UKA or TKA. These were compared with 14 preop patients and 14 normal controls. Their gait was measured at increasing speeds on a treadmill instrumented with force plates. Both arthroplasty groups were significantly faster than the preop OA group. TKA patients walked substantially faster than any previously reported series of knee arthroplasties. UKA patients walked 10% faster than TKA, although not as fast as the normal controls. Stride length was 5% greater and stance time 7% shorter following UKA — both much closer to normal than TKA. Unlike TKA, UKA enables a near normal gait one year after surgery.

Wiik, Anatole V.; Manning, Victoria; Strachan, Robin K.; Amis, Andrew A.; Cobb, Justin Peter

2013-01-01

262

Cryogenic turbopump bearing materials  

NASA Technical Reports Server (NTRS)

Materials used for modern cryogenic turbopump bearings must withstand extreme conditions of loads and speeds under marginal lubrication. Naturally, these extreme conditions tend to limit the bearing life. It is possible to significantly improve the life of these bearings, however, by improving the fatigue and wear resistance of bearing alloys, and improving the strength, liquid oxygen compatibility and lubricating ability of the bearing cage materials. Improved cooling will also help to keep the bearing temperatures low and hence prolong the bearing life.

Bhat, Biliyar N.

1989-01-01

263

Autonomous Evolution of Dynamic Gaits with Two Quadruped Robots  

NASA Technical Reports Server (NTRS)

A challenging task that must be accomplished for every legged robot is creating the walking and running behaviors needed for it to move. In this paper we describe our system for autonomously evolving dynamic gaits on two of Sony's quadruped robots. Our evolutionary algorithm runs on board the robot and uses the robot's sensors to compute the quality of a gait without assistance from the experimenter. First we show the evolution of a pace and trot gait on the OPEN-R prototype robot. With the fastest gait, the robot moves at over 10/min/min., which is more than forty body-lengths/min. While these first gaits are somewhat sensitive to the robot and environment in which they are evolved, we then show the evolution of robust dynamic gaits, one of which is used on the ERS-110, the first consumer version of AIBO.

Hornby, Gregory S.; Takamura, Seichi; Yamamoto, Takashi; Fujita, Masahiro

2004-01-01

264

Hamstring and psoas length of crouch gait in cerebral palsy: a comparison with induced crouch gait in age- and sex-matched controls  

PubMed Central

Background Previous studies have shown that hamstring lengths are often not short in patients with cerebral palsy, which raises concerns over the benefits of distal hamstring lengthening in patients with crouch gait. In this study, the authors measured lengths of hamstrings and psoas muscles in normal subjects mimicking crouch gait and compared these with lengths in cerebral palsy patients with crouch gait. Methods Thirty-six patients with cerebral palsy and crouch gait were included in this study, and in addition, 36 age- and sex-matched normal controls were recruited. Hamstring and psoas muscle lengths in patients were evaluated using gait analysis and interactive musculoskeletal modeling software. Muscle lengths were also measured in the normal control group during normal gait and while mimicking crouch gait, and these were compared with those of cerebral palsy patient with crouch gait. Results No significant differences were observed between maximum hamstring (p=0.810) and maximum psoas (p=0.456) lengths of patients and controls mimicking crouch gait. However, patients showed significantly shorter excursions of hamstring (p=0.022) and psoas (p=0.036) muscles than controls, whereas no significant excursion differences were observed between controls during normal gait and mimicking crouch gait. Conclusions Normal controls mimicking crouch gait and cerebral palsy patients with crouch gait demonstrate similar muscle length patterns. However, mimicked crouch gait did not reproduce the excursion pattern shown by patients with crouch gait, which suggests that reduced hamstring and psoas excursion is an innate characteristic of pathologic crouch gait.

2013-01-01

265

Zernike moments features for shape-based gait recognition  

NASA Astrophysics Data System (ADS)

The paper proposes a new spatio-temporal gait representation, called cycles gait Zernike moments (CGZM), to characterize human walking properties for individual recognition. Firstly, Zernike moments as shape descriptors are used to characterize gait silhouette shape. Secondly, we generate CGZM from Zernike moments of silhouette sequences. Finally, the phase and magnitude coefficientsof CGZM are utilized to perform classification by the modified Hausdorff distance (MHD) classifier. Experimental results show that the proposed approach have an encouraging recognition performance.

Qin, Huanfeng; Qin, Lan; Liu, Jun; Chao, Jiang

2011-08-01

266

Balance and gait in children with dyslexia  

Microsoft Academic Search

  \\u000a Tests of postural stability have provided some evidence of a link between deficits in gross motor skills and developmental\\u000a dyslexia. The ordinal-level scales used previously, however, have limited measurement sensitivity, and no studies have investigated\\u000a motor performance during walking in participants with dyslexia. The purpose of this study was to investigate if continuous-scaled\\u000a measures of standing balance and gait

Rolf Moe-Nilssen; Jorunn L. Helbostad; Joel B. Talcott; Finn Egil Toennessen

2003-01-01

267

Gait problems in diabetic neuropathic patients  

Microsoft Academic Search

Objective: To examine whether a reduced peripheral sensibility caused by diabetic neuropathy increases the attentional demands necessary for controlling and regulating gait.Design: Nonrandomized control trial.Setting: University motor performance laboratory.Subjects: Twelve diabetic patients with peripheral neuropathy and 7 control subjects, all volunteers.Interventions: All subjects first performed a control seated reaction time task. For the walking task, auditory stimuli were randomly presented

Richard Courtemanche; Normand Teasdale; Pierre Boucher; Michelle Fleury; Yves Lajoie; Chantal Bard

1996-01-01

268

Gait patterns for crime fighting: statistical evaluation  

NASA Astrophysics Data System (ADS)

The criminality is omnipresent during the human history. Modern technology brings novel opportunities for identification of a perpetrator. One of these opportunities is an analysis of video recordings, which may be taken during the crime itself or before/after the crime. The video analysis can be classed as identification analyses, respectively identification of a person via externals. The bipedal locomotion focuses on human movement on the basis of their anatomical-physiological features. Nowadays, the human gait is tested by many laboratories to learn whether the identification via bipedal locomotion is possible or not. The aim of our study is to use 2D components out of 3D data from the VICON Mocap system for deep statistical analyses. This paper introduces recent results of a fundamental study focused on various gait patterns during different conditions. The study contains data from 12 participants. Curves obtained from these measurements were sorted, averaged and statistically tested to estimate the stability and distinctiveness of this biometrics. Results show satisfactory distinctness of some chosen points, while some do not embody significant difference. However, results presented in this paper are of initial phase of further deeper and more exacting analyses of gait patterns under different conditions.

Sulovská, Kate?ina; B?lašková, Silvie; Adámek, Milan

2013-10-01

269

Gait correlation analysis based human identification.  

PubMed

Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x), vertical axis (y), and temporal axis (t). By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features' dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance. PMID:24592144

Chen, Jinyan

2014-01-01

270

Evaluating alternative gait strategies using evolutionary robotics  

PubMed Central

Evolutionary robotics is a branch of artificial intelligence concerned with the automatic generation of autonomous robots. Usually the form of the robot is predefined and various computational techniques are used to control the machine's behaviour. One aspect is the spontaneous generation of walking in legged robots and this can be used to investigate the mechanical requirements for efficient walking in bipeds. This paper demonstrates a bipedal simulator that spontaneously generates walking and running gaits. The model can be customized to represent a range of hominoid morphologies and used to predict performance parameters such as preferred speed and metabolic energy cost. Because it does not require any motion capture data it is particularly suitable for investigating locomotion in fossil animals. The predictions for modern humans are highly accurate in terms of energy cost for a given speed and thus the values predicted for other bipeds are likely to be good estimates. To illustrate this the cost of transport is calculated for Australopithecus afarensis. The model allows the degree of maximum extension at the knee to be varied causing the model to adopt walking gaits varying from chimpanzee-like to human-like. The energy costs associated with these gait choices can thus be calculated and this information used to evaluate possible locomotor strategies in early hominids.

Sellers, William I; Dennis, Louise A; Wang, W -J; Crompton, Robin H

2004-01-01

271

Managing variability in the summary and comparison of gait data.  

PubMed

Variability in quantitative gait data arises from many potential sources, including natural temporal dynamics of neuromotor control, pathologies of the neurological or musculoskeletal systems, the effects of aging, as well as variations in the external environment, assistive devices, instrumentation or data collection methodologies. In light of this variability, unidimensional, cycle-based gait variables such as stride period should be viewed as random variables and prototypical single-cycle kinematic or kinetic curves ought to be considered as random functions of time. Within this framework, we exemplify some practical solutions to a number of commonly encountered analytical challenges in dealing with gait variability. On the topic of univariate gait variables, robust estimation is proposed as a means of coping with contaminated gait data, and the summary of non-normally distributed gait data is demonstrated by way of empirical examples. On the summary of gait curves, we discuss methods to manage undesirable phase variation and non-robust spread estimates. To overcome the limitations of conventional comparisons among curve landmarks or parameters, we propose as a viable alternative, the combination of curve registration, robust estimation, and formal statistical testing of curves as coherent units. On the basis of these discussions, we provide heuristic guidelines for the summary of gait variables and the comparison of gait curves. PMID:16053523

Chau, Tom; Young, Scott; Redekop, Sue

2005-01-01

272

Managing variability in the summary and comparison of gait data  

PubMed Central

Variability in quantitative gait data arises from many potential sources, including natural temporal dynamics of neuromotor control, pathologies of the neurological or musculoskeletal systems, the effects of aging, as well as variations in the external environment, assistive devices, instrumentation or data collection methodologies. In light of this variability, unidimensional, cycle-based gait variables such as stride period should be viewed as random variables and prototypical single-cycle kinematic or kinetic curves ought to be considered as random functions of time. Within this framework, we exemplify some practical solutions to a number of commonly encountered analytical challenges in dealing with gait variability. On the topic of univariate gait variables, robust estimation is proposed as a means of coping with contaminated gait data, and the summary of non-normally distributed gait data is demonstrated by way of empirical examples. On the summary of gait curves, we discuss methods to manage undesirable phase variation and non-robust spread estimates. To overcome the limitations of conventional comparisons among curve landmarks or parameters, we propose as a viable alternative, the combination of curve registration, robust estimation, and formal statistical testing of curves as coherent units. On the basis of these discussions, we provide heuristic guidelines for the summary of gait variables and the comparison of gait curves.

Chau, Tom; Young, Scott; Redekop, Sue

2005-01-01

273

A portable system with sample rate of 250 Hz for characterization of knee and hip angles in the sagittal plane during gait  

PubMed Central

Background Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted. Methods The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters. Results The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype. Conclusions The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system.

2014-01-01

274

SSM-HPC: Front View Gait Recognition Using Spherical Space Model with Human Point Clouds  

NASA Astrophysics Data System (ADS)

In this paper, we propose a novel gait recognition framework - Spherical Space Model with Human Point Clouds (SSM-HPC) to recognize front view of human gait. A new gait representation - Marching in Place (MIP) gait is also introduced which preserves the spatiotemporal characteristics of individual gait manner. In comparison with the previous studies on gait recognition which usually use human silhouette images from image sequences, this research applies three dimensional (3D) point clouds data of human body obtained from stereo camera. The proposed framework exhibits gait recognition rates superior to those of other gait recognition methods.

Ryu, Jegoon; Kamata, Sei-Ichiro; Ahrary, Alireza

275

Gait asymmetry in patients with Parkinson’s disease and elderly fallers: when does the bilateral coordination of gait require attention?  

Microsoft Academic Search

While it is known that certain pathologies may impact on left–right symmetry of gait, little is known about the mechanisms\\u000a that contribute to gait symmetry or how high in the hierarchy of the control of gait symmetry is regulated in humans. To assess\\u000a the contribution of cognitive function to gait symmetry, we measured gait asymmetry (GA) in three subject groups,

Galit Yogev; Meir Plotnik; Chava Peretz; Nir Giladi; Jeffrey M. Hausdorff

2007-01-01

276

Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training  

PubMed Central

Background Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on individuals with incomplete spinal cord injury (iSCI). Methods Eleven patients with iSCI participated in a single training session with the gait rehabilitation robot Lokomat. The patients were exposed to four different training modes in random order: During both non-cooperative position control and compliant impedance control, fixed timing of movements was provided. During two variants of the patient-cooperative path control approach, free timing of movements was enabled and the robot provided only spatial guidance. The two variants of the path control approach differed in the amount of additional support, which was either individually adjusted or exaggerated. Joint angles and torques of the robot as well as muscle activity and heart rate of the patients were recorded. Kinematic variability, interaction torques, heart rate and muscle activity were compared between the different conditions. Results Patients showed more spatial and temporal kinematic variability, reduced interaction torques, a higher increase of heart rate and more muscle activity in the patient-cooperative path control mode with individually adjusted support than in the non-cooperative position control mode. In the compliant impedance control mode, spatial kinematic variability was increased and interaction torques were reduced, but temporal kinematic variability, heart rate and muscle activity were not significantly higher than in the position control mode. Conclusions Patient-cooperative robot-aided gait training with free timing of movements made individuals with iSCI participate more actively and with larger kinematic variability than non-cooperative, position-controlled robot-aided gait training.

2010-01-01

277

Alterations in gait speed and age do not fully explain the changes in gait mechanics associated with healthy older women.  

PubMed

Older adults exhibit modified gait patterns compared to the young, adopting movement strategies in response to changes in musculoskeletal function. Investigating the functional mobility of older women is particularly important because of their increased life expectancy and greater falls risk compared to men. We explored the relationships between gait parameters and age in healthy older women whilst accounting for declining gait speeds. Kinematic and kinetic data were collected from thirty-nine women (60-83 years) whilst walking at a comfortable cadence. Regression analysis assessed the capacity of gait speed and age to explain the variance in gait associated with older age. Speed explained the majority of variance in many gait parameters. By including age in the regression, the total explained variance (R2) for foot clearance (70%), ankle plantarflexion angle (30%), peak ankle plantarflexor moment (58%), and hip power generation (56%) were significantly (p<0.05) greater than for speed alone. Nonetheless, changes in speed and age did not fully explain the variance in gait mechanics associated with older age and other contributing factors must exist. Losses of 1.2%/year in gait speed were predicted by age, exceeding previous predictions of -0.7%/year. Furthermore, the accumulation of apparently small decreases of 0.2 cm/year in peak foot-to-ground clearance has clinical implications and offers insight into the mechanisms by which gait becomes hazardous in older age. PMID:23122897

Alcock, L; Vanicek, N; O'Brien, T D

2013-04-01

278

Bearings for Extreme Environments.  

National Technical Information Service (NTIS)

Dry lubricated bearings for applications under extreme environmental conditions were developed. Results with ball bearings assembled from bearing rings coated with hard carbide layers, steel balls, and cages of various materials with self-lubricating prop...

H. Gass H. E. Hintermann G. Stehle H. M. Briscoe

1975-01-01

279

A systematic review of the efficacy of gait rehabilitation strategies for spinal cord injury  

PubMed Central

OBJECTIVE To systematically review the evidence for the efficacy of different rehabilitation strategies on functional ambulation following spinal cord injury (SCI). METHODS A keyword literature search of original articles was used to identify published literature evaluating the effectiveness of any treatment or therapy on functional ambulation in people with SCI. The rigor and quality of each study were scored on standardized scales by two independent reviewers. RESULTS The search yielded 160 articles, of which 119 were excluded for not meeting our inclusion criteria. The remaining 41 articles covered various strategies for improving gait: bodyweight supported treadmill training (BWSTT) (n=12), functional electrical stimulation (FES) (n=7), braces/orthoses (n=10), or a combination of these (n=12). There is strong evidence from randomized controlled trials that functional ambulation outcomes following body-weight supported treadmill training (BWSTT) are comparable to an equivalent intensity of overground gait training in sub-acute SCI. In chronic SCI, evidence from pre-test/post-test studies shows that BWSTT may be effective in improving functional ambulation. Pre-test/post-test or post-test only studies provide evidence that FES may augment functional ambulation in sub-acute/chronic SCI while braces may afford particular benefits to people with complete SCI to stand up and ambulate with assistive devices. CONCLUSIONS Rehabilitation strategies that facilitate repeated practice of gait offer the greatest benefits to functional ambulation in sub-acute or chronic SCI. Supportive devices may augment functional ambulation particularly in people with incomplete SCI.

Lam, Tania; Eng, Janice J; Wolfe, Dalton L; Hsieh, Jane T; Whittaker, Maura

2012-01-01

280

Gait learning method for stable motion using quadrupedal robot  

Microsoft Academic Search

In the field of pet robots and robot-assisted therapy (RAT), characterization of animal motion is important for the development of robots resembling various animals. This paper presents a method for the generation of animal gait in quadrupedal robots. In this study, we employed AIBO as an experimental quadrupedal robot and generated the gait of the robot on the basis of

Hidekazu Suzuki; Hitoshi Nishi; Seiya Tsuchiya

2010-01-01

281

Individual Recognition by Kinematic-Based Gait Analysis  

Microsoft Academic Search

Current gait recognition approaches only consider individuals walking frontopamllel to the image plane. This makes them inapplicoble for recognizing individuals walking from different angles with respect to the image plane. In this paper, we propose a kinematic-based approach to recognize individuals by gait. The proposed approach estimates 30 human walking parameters by performing a least squares fit of the 30

Bir Bhanu; Ju Han

2002-01-01

282

Detecting Walking Gait Impairment with an Ear-worn Sensor  

Microsoft Academic Search

This paper investigates an ear worn sensor for the development of a gait analysis framework. Instead of explicitly defining gait features that indicate injury or impairment, an automatic method of feature extraction and selection is proposed. The proposed framework uses multi-resolution wavelet analysis and margin based feature selection. It was validated on three datasets; the first simulating a leg injury,

Louis Atallah; Omer Aziz; Benny P. L. Lo; Guang-zhong Yang

2009-01-01

283

Automatic gait recognition based on statistical shape analysis  

Microsoft Academic Search

Gait recognition has recently gained significant at- tention from computer vision researchers. This interest is strongly motivated by the need for automated person identification systems at a distance in visual surveillance and monitoring applications. As a newly emergent biometric feature, gait is a particularly at- tractive modality from the surveillance point of view. This paper aims to propose a simple

Liang Wang; Tieniu Tan; Weiming Hu; Huazhong Ning

2003-01-01

284

Generation of Energy Optimal Complete Gait Cycles for Biped Robots  

Microsoft Academic Search

Abstract: In this paper we address the problem of energyoptimalgait generation for biped robots. Using a simplied robot dynamics that ignores the eoeects of centripetalforces, we obtain unconstrained optimal trajectoriesgenerated by piecewise constant inputs. Westudy a complete gait cycle comprising single support,double support and the transition phases. The energyoptimal gaits for dioeerent step lengths and velocitiesare compared with natural human

L. Roussel; Carlos Canudas De Wit; Ambarish Goswami

1998-01-01

285

Gait disorders and fall risk: Detection and prevention  

Microsoft Academic Search

Elderly patients are at risk for high levels of morbidity and mortality from falls related to gait disorders. Gait disorders\\u000a are often missed in clinical practice but can be easily detected and characterized so at-risk patients can be given appropriate\\u000a therapy.

Andrew S. Duxbury

2000-01-01

286

Real-time gait event detection for paraplegic FES walking  

Microsoft Academic Search

A real-time method for the detection of gait events that occur during the electrically stimulated locomotion of paraplegic subjects is described. It consists of a two-level algorithm for the processing of sensor signals and the determination of gait event times. Sensor signals and information about the progression of the stimulator though its pre-specified stimulation \\

Margaret M. Skelly; Howard Jay Chizeck

2001-01-01

287

A continuous-wave (CW) radar for gait analysis  

Microsoft Academic Search

A fully coherent, continuous-wave (CW) radar operating near 10.5 GHz has been developed to record the radar signature corresponding to the walking human gait. The received signal is the sum of Doppler shifted signals reflected from the various parts of the moving body. Since the legs, arms, and torso all move at different relative velocities throughout the gait cycle, the

Jonathan L. Geisheimer; William S. Marshall; Eugene Greneker

2001-01-01

288

Clinical gait analysis by neural networks: issues and experiences  

Microsoft Academic Search

Clinical gait analysis is an area aiming at the provision of support for diagnoses and therapyconsiderations, the development of bio-feedback systems to train patients, and the recognition ofeffects of multiple diseases and still active compensation. The data recorded with ground reactionforce measurement platforms is a convenient starting point for gait analysis. We argue in favor ofusing the raw data from

Monika Köhle; Dieter Merkl; Josef Kastner

1997-01-01

289

Methods, Applications and Limitations of Gait Analysis in Horses  

Microsoft Academic Search

Over the last 30 years, the increase in interest in horses for racing and riding activities has stimulated scientific research in equine locomotion. This paper presents a review of the measurement methods and their applications used to assess equine locomotion. After describing gaits and velocity-related changes in stride variables, the current applications of gait analysis are presented. The economic consequences

E. BARREY

1999-01-01

290

Gait biomechanics and the evolution of total joint replacement  

Microsoft Academic Search

The history and evolution of total knee and total hip replacement has been influenced substantially by the knowledge obtained from gait analysis studies. Many of the mechanical problems associated with these devices have been analyzed and evaluated in terms of the mechanics of walking. The magnitude and pattern of the forces at the hip and knee joints derived from gait

Thomas P. Andriacchi; Debra E. Hurwitz

1997-01-01

291

Gait and electromyographic analysis of anterior cruciate ligament deficient subjects  

Microsoft Academic Search

Some anterior cruciate ligament deficient (ACLD) patients can overcome passive sagittal joint laxity and maintain dynamic stability of the knee joint. Gait analysis with electromyographic (EMG) support was used in an attempt to identify mechanisms whereby ACLD individuals achieve this functional stability. A group of 18 patients with arthroscopically proven, unilateral, chronic (>6 months) ACLD had their gait assessed using

D. J. Beard; R. S. Soundarapandian; J. J. O'Connor; C. A. F. Dodd

1996-01-01

292

DRAG: a database for recognition and analasys of gait  

NASA Astrophysics Data System (ADS)

A novel approach is proposed for creating a standardized and comprehensive database for gait analysis. The field of gait analysis is gaining increasing attention for applications such as visual surveillance, human-computer interfaces, and gait recognition and rehabilitation. Numerous algorithms have been developed for analyzing and processing gait data; however, a standard database for their systematic evaluation does not exist. Instead, existing gait databases consist of subsets of kinematic, kinetic, and electromyographic activity recordings by different investigators, at separate laboratories, and under varying conditions. Thus, the existing databases are neither homogenous nor sufficiently populated to statistically validate the algorithms. In this paper, a methodology for creating a database is presented, which can be used as a common ground to test the performance of algorithms that rely upon external marker data, ground reaction loading data, and/or video images. The database consists of: (1) synchronized motion-capture data (3D marker data) obtained using external markers, (2) computed joint angles, and (3) ground reaction loading acquired with plantar pressure insoles. This database could be easily expanded to include synchronized video, which will facilitate further development of video-based algorithms for motion tracking. This eventually could lead to the realization of markerless gait tracking. Such a system would have extensive applications in gait recognition, as well as gait rehabilitation. The entire database (marker, angle, and force data) will be placed in the public domain, and made available for downloads over the World Wide Web.

Kuchi, Prem; Hiremagalur, Raghu Ram V.; Huang, Helen; Carhart, Michael; He, Jiping; Panchanathan, Sethuraman

2003-11-01

293

Bounding Gait in a Hybrid Wheeled-Leg Robot  

Microsoft Academic Search

This paper discusses the first implementation of a dynamically stable bounding gait on a hybrid wheeled-leg robot. Design of the robot is reviewed and the controllers which allow this mode of mobility to occur are discussed. Experimental results demonstrating the key dynamic characteristics of the gait, including footfall patterns, are given. The hypothesis that varying leg takeoff angles can lead

James Andrew Smith; Inna Sharf; Michael Trentini

2006-01-01

294

Stretch reflex contribution to soleus activation during spastic gait  

Microsoft Academic Search

The authors studied the ankle extensor stretch reflex contribution to locomotor EMG for spastic gait by relating ankle angular velocity and soleus electromyography (EMG). The perturbations induced by the load variation during free gait were sufficient to characterize the stretch reflex contribution to soleus EMG during the beginning of the stance phase. Dorsiflexion peaks in the averaged ankle angular velocity

Peter H. Veltink; M. Ladouceur; T. Sinkjaer

1998-01-01

295

Silhouette Analysis-Based Gait Recognition for Human Identification  

Microsoft Academic Search

Human identification at a distance has recently gained growing interest from computer vision researchers. Gait recognition aims essentially to address this problem by identifying people based on the way they walk. In this paper, a simple but efficient gait recognition algorithm using spatial-temporal silhouette analysis is proposed. For each image sequence, a background subtraction algorithm and a simple correspondence procedure

Liang Wang; Tieniu Tan; Huazhong Ning; Weiming Hu

2003-01-01

296

Abnormal joint torque patterns exhibited by chronic stroke subjects while walking with a prescribed physiological gait pattern  

PubMed Central

Background It is well documented that individuals with chronic stroke often exhibit considerable gait impairments that significantly impact their quality of life. While stroke subjects often walk asymmetrically, we sought to investigate whether prescribing near normal physiological gait patterns with the use of the Lokomat robotic gait-orthosis could help ameliorate asymmetries in gait, specifically, promote similar ankle, knee, and hip joint torques in both lower extremities. We hypothesized that hemiparetic stroke subjects would demonstrate significant differences in total joint torques in both the frontal and sagittal planes compared to non-disabled subjects despite walking under normal gait kinematic trajectories. Methods A motion analysis system was used to track the kinematic patterns of the pelvis and legs of 10 chronic hemiparetic stroke subjects and 5 age matched controls as they walked in the Lokomat. The subject's legs were attached to the Lokomat using instrumented shank and thigh cuffs while instrumented footlifters were applied to the impaired foot of stroke subjects to aid with foot clearance during swing. With minimal body-weight support, subjects walked at 2.5 km/hr on an instrumented treadmill capable of measuring ground reaction forces. Through a custom inverse dynamics model, the ankle, knee, and hip joint torques were calculated in both the frontal and sagittal planes. A single factor ANOVA was used to investigate differences in joint torques between control, unimpaired, and impaired legs at various points in the gait cycle. Results While the kinematic patterns of the stroke subjects were quite similar to those of the control subjects, the kinetic patterns were very different. During stance phase, the unimpaired limb of stroke subjects produced greater hip extension and knee flexion torques than the control group. At pre-swing, stroke subjects inappropriately extended their impaired knee, while during swing they tended to abduct their impaired leg, both being typical abnormal torque synergy patterns common to stroke gait. Conclusion Despite the Lokomat guiding stroke subjects through physiologically symmetric kinematic gait patterns, abnormal asymmetric joint torque patterns are still generated. These differences from the control group are characteristic of the hip hike and circumduction strategy employed by stroke subjects.

Neckel, Nathan D; Blonien, Natalie; Nichols, Diane; Hidler, Joseph

2008-01-01

297

Effects of military load carriage on kinematics of gait.  

PubMed

Manual load carriage is a universal activity and an inevitable part of the daily schedule of a soldier. Indian Infantry soldiers carry loads on the waist, back, shoulders and in the hands for a marching order. There is no reported study on the effects of load on gait in this population. It is important to evaluate their kinematic responses to existing load carriage operations and to provide guidelines towards the future design of heavy military backpacks (BPs) for optimising soldiers' performance. Kinematic changes of gait parameters in healthy male infantry soldiers whilst carrying no load (NL) and military loads of 4.2-17.5 kg (6.5-27.2% body weight) were investigated. All comparisons were conducted at a self-selected speed. Soldier characteristics were: mean (SD) age 23.3 (2.6) years; height 172.0 (3.8) cm; weight 64.3 (7.4) kg. Walk trials were collected using a 3-D Motion Analysis System. Results were subjected to one-way ANOVA followed by Dunnett post hoc test. There were increases in step length, stride length, cadence and midstance with the addition of a load compared to NL. These findings were resultant of an adaptive phenomenon within the individual to counterbalance load effect along with changes in speed. Ankle and hip ranges of motion (ROM) were significant. The ankle was more dorsiflexed, the knee and hip were more flexed during foot strike and helped in absorption of the load. The trunk showed more forward leaning with the addition of a load to adjust the centre of mass of the body and BP system back to the NL condition. Significant increases in ankle and hip ROM and trunk forward inclination (> or =10 degrees ) with lighter loads, such as a BP (10.7 kg), BP with rifle (14.9 kg) and BP with a light machine gun (17.5 kg), may cause joint injuries. It is concluded that the existing BP needs design improvisation specifically for use in low intensity conflict environments. STATEMENT OF RELEVANCE: The present study evaluates spatial, temporal and angular changes at trunk and limb joints during military load carriage of relatively lighter magnitude. Studies on similar aspects on the specific population are limited. These data can be used for optimising load carriage and designing ensembles, especially a heavy BP, for military operations. PMID:20496244

Majumdar, Deepti; Pal, Madhu Sudan; Majumdar, Dhurjati

2010-06-01

298

Concurrent validity of accelerometry to measure gait in Parkinsons Disease.  

PubMed

The Vitaport Activity Monitor (VAM) is an ambulatory monitoring device that uses accelerometer signals to assess the quality and quantity of walking and mobility related activities in home and community. The objective of this study was to investigate the concurrent validity of the VAM and GAITRite((R)) to measure gait speed, step length and step frequency during a test of functional gait that included single, dual and multiple task components for 12 people with Parkinsons Disease (PD) and 11 comparisons participating. For PD participants, ICCs were excellent for all gait variables (ICC (2, 2)=0.92-0.99, p< or =0.0001). For control participants, ICCs were good to excellent for all gait variables (ICC (2, 2)=0.74-0.94, p< or =0.05). Mean score differences between the two instruments were greatest for step frequency for both PD and comparisons. The VAM is useful for objective gait measurement in the home and community. PMID:17604630

Lord, Sue; Rochester, Lynn; Baker, Katherine; Nieuwboer, Alice

2008-02-01

299

The biomechanics of skipping gaits: a third locomotion paradigm?  

PubMed Central

Skipping, a gait children display when they are about four- to five-years-old, is revealed to be more than a behavioural peculiarity. By means of metabolic and biomechanical measurements at several speeds, the relevance of skipping is shown to extend from links between bipedal and quadrupedal locomotion (namely galloping) to understanding why it could be a gait of choice in low-gravity conditions, and to some aspects of locomotion evolution (ground reaction forces of skipping seem to originate from pushing the walking gait to unnaturally high speeds). When the time-courses of mechanical energy and the horizontal ground reaction force are considered, a different locomotion paradigm emerges, enabling us to separate, among the bouncing gaits, the trot from the gallop (quadrupeds) and running from skipping (bipeds). The simultaneous use of pendulum-like and elastic mechanisms in skipping gaits, as shown by the energy curve analysis, helps us to understand the low cost of transport of galloping quadrupeds.

Minetti, A E

1998-01-01

300

Design and test of a magnetic thrust bearing  

NASA Technical Reports Server (NTRS)

A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

1993-01-01

301

Patterns of muscle coordination vary with stride frequency during weight assisted treadmill walking  

Microsoft Academic Search

Partial body weight-supported treadmill training is an approach for gait rehabilitation. Variables such as stepping frequency and the amount of body weight support are key parameters manipulated during training. The purpose of this study was to quantify the extent to which body weight support and stride frequency contribute and interact to produce the coordination patterns of the leg muscles. Principal

Taryn Klarner; Henry K. Chan; James M. Wakeling; Tania Lam

2010-01-01

302

Powered lower limb orthoses for gait rehabilitation  

PubMed Central

Bodyweight supported treadmill training has become a prominent gait rehabilitation method in leading rehabilitation centers. This type of locomotor training has many functional benefits but the labor costs are considerable. To reduce therapist effort, several groups have developed large robotic devices for assisting treadmill stepping. A complementary approach that has not been adequately explored is to use powered lower limb orthoses for locomotor training. Recent advances in robotic technology have made lightweight powered orthoses feasible and practical. An advantage to using powered orthoses as rehabilitation aids is they allow practice starting, turning, stopping, and avoiding obstacles during overground walking.

Ferris, Daniel P.; Sawicki, Gregory S.; Domingo, Antoinette

2006-01-01

303

Dynamic locomotion of a biomorphic quadruped 'Tekken' robot using various gaits: walk, trot, free-gait and bound  

Microsoft Academic Search

Numerous quadruped walking and running robots have been developed to date. Each robot walks by means of a crawl, walk, trot or pace gait, or runs by means of a bound and\\/or gallop gait. However, it is very difficult to design a single robot that can both walk and run because of problems related to mechanisms and control. In response

Y. Fukuokaa; H. Kimura

2009-01-01

304

Thrust bearing for turbocharger  

Microsoft Academic Search

A thrust bearing is described for sustaining the thrust load of the rotor shaft of a turbocharger, the thrust bearing having a first and second opposed side surface, comprising: A first groove formed in the first side surface of the thrust bearing for holding lubricating oil supplied to the bearing; at least one first oil passage extending from the groove

T. Tamura; N. Shibata; T. Kawakami

1987-01-01

305

Passive magnetic bearing configurations  

DOEpatents

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Post, Richard F. (Walnut Creek, CA) [Walnut Creek, CA

2011-01-25

306

Getting Your Bearings  

NSDL National Science Digital Library

In this activity, learners explore the concept of friction and how ball bearings reduce friction. Learners investigate different uses for ball bearings, how the design has changed over time to incorporate roller bearings, test friction using marbles, and identify the use of ball bearings in everyday items.

Ieee

2013-08-30

307

Characteristic Gait Patterns in Older Adults with Obesity - Results from the Baltimore Longitudinal Study of Aging  

PubMed Central

Obesity in older adults is a growing public health problem. Excess weight causes biomechanical burden to lower extremity joints and contribute to joint pathology. The aim of this study was to identify specific characteristics of gait associated with body mass index (BMI). Preferred and maximum speed walking and related gait characteristics were examined in 164 (50–84 years) participants from Baltimore Longitudinal Study of Aging (BLSA) able to walk unassisted. Participants were divided into three groups based on their BMI: normal weight (19 ? BMI < 25 kg/m2), overweight (25 ? BMI < 30 kg/m2) and obese (BMI 30 ? BMI < 40 kg/m2). Total ankle generative mechanical work expenditure (MWE) in the anterior-posterior (AP) plane was progressively and significantly lower with increasing BMI for both preferred (p = 0.026) and maximum speed walking (p < 0.001). In the medial-lateral (ML) plane, total knee generative MWE was higher in obese participants in the preferred speed task (p = 0.002), and total hip absorptive MWE was higher in obese in both preferred speed (p < 0.001) and maximum speed (p = 0.002) walking task compared to the normal weight participants. Older adults with obesity show spatiotemporal gait patterns which may help to reduce contact impacts. In addition, in obese persons mechanical energy usages tend to be lower in the AP plane and higher in the ML plane. Since forward progression forces are mainly implicated in normal walking, this pattern found in obese participants is suggestive of lower energetic efficiency.

Ko, Seung-uk; Stenholm, Sari; Ferrucci, Luigi

2010-01-01

308

Performance Analysis of Time-Distance Gait Parameters under Different Speeds  

Microsoft Academic Search

This paper explores gait recognition for various walking speeds. Normal-constant speed is one of the assumptions being made in many current gait recognition techniques. However, some techniques do not scale well when certain gait conditions such as walking speed varies. We demonstrate the characteristics of time-distance gait parameters, stride length and cadence, with respect to walking speed at the inter-

Rawesak Tanawongsuwan; Aaron F. Bobick

2003-01-01

309

How much muscle strength is required to walk in a crouch gait?  

PubMed

Muscle weakness is commonly cited as a cause of crouch gait in individuals with cerebral palsy; however, outcomes after strength training are variable and mechanisms by which muscle weakness may contribute to crouch gait are unclear. Understanding how much muscle strength is required to walk in a crouch gait compared to an unimpaired gait may provide insight into how muscle weakness contributes to crouch gait and assist in the design of strength training programs. The goal of this study was to examine how much muscle groups could be weakened before crouch gait becomes impossible. To investigate this question, we first created muscle-driven simulations of gait for three typically developing children and six children with cerebral palsy who walked with varying degrees of crouch severity. We then simulated muscle weakness by systematically reducing the maximum isometric force of each muscle group until the simulation could no longer reproduce each subject's gait. This analysis indicated that moderate crouch gait required significantly more knee extensor strength than unimpaired gait. In contrast, moderate crouch gait required significantly less hip abductor strength than unimpaired gait, and mild crouch gait required significantly less ankle plantarflexor strength than unimpaired gait. The reduced strength required from the hip abductors and ankle plantarflexors during crouch gait suggests that weakness of these muscle groups may contribute to crouch gait and that these muscle groups are potential targets for strength training. PMID:22959837

Steele, Katherine M; van der Krogt, Marjolein M; Schwartz, Michael H; Delp, Scott L

2012-10-11

310

How much muscle strength is required to walk in a crouch gait?  

PubMed Central

Muscle weakness is commonly cited as a cause of crouch gait in individuals with cerebral palsy; however, outcomes after strength training are variable and mechanisms by which muscle weakness may contribute to crouch gait are unclear. Understanding how much muscle strength is required to walk in a crouch gait compared to an unimpaired gait may provide insight into how muscle weakness contributes to crouch gait and assist in the design of strength training programs. The goal of this study was to examine how much muscle groups could be weakened before crouch gait becomes impossible. To investigate this question, we first created muscle-driven simulations of gait for three typically-developing children and six children with cerebral palsy who walked with varying degrees of crouch severity. We then simulated muscle weakness by systematically reducing the maximum isometric force of each muscle group until the simulation could no longer reproduce each subject’s gait. This analysis indicated that moderate crouch gait required significantly more knee extensor strength than unimpaired gait. In contrast, moderate crouch gait required significantly less hip abductor strength than unimpaired gait, and mild crouch gait required significantly less ankle plantarflexor strength than unimpaired gait. The reduced strength required from the hip abductors and ankle plantarflexors during crouch gait suggests that weakness of these muscle groups may contribute to crouch gait and that these muscle groups are potential targets for strength training.

Steele, Katherine M.; van der Krogt, Marjolein M.; Schwartz, Michael H.; Delp, Scott L.

2012-01-01

311

Rolling-Element Bearings  

NASA Technical Reports Server (NTRS)

Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

Hamrock, B. J.; Anderson, W. J.

1983-01-01

312

Introduction to ball bearings  

NASA Technical Reports Server (NTRS)

The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

Hamrock, B. J.; Dowson, D.

1981-01-01

313

High efficiency magnetic bearings  

NASA Technical Reports Server (NTRS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

1993-01-01

314

A collisional perspective on quadrupedal gait dynamics.  

PubMed

The analysis of terrestrial locomotion over the past half century has focused largely on strategies of mechanical energy recovery used during walking and running. In contrast, we describe the underlying mechanics of legged locomotion as a collision-like interaction that redirects the centre of mass (CoM). We introduce the collision angle, determined by the angle between the CoM force and velocity vectors, and show by computing the collision fraction, a ratio of actual to potential collision, that the quadrupedal walk and gallop employ collision-reduction strategies while the trot permits greater collisions. We provide the first experimental evidence that a collision-based approach can differentiate quadrupedal gaits and quantify interspecific differences. Furthermore, we show that this approach explains the physical basis of a commonly used locomotion metric, the mechanical cost of transport. Collision angle and collision fraction provide a unifying analysis of legged locomotion which can be applied broadly across animal size, leg number and gait. PMID:21471189

Lee, David V; Bertram, John E A; Anttonen, Jennifer T; Ros, Ivo G; Harris, Sarah L; Biewener, Andrew A

2011-10-01

315

Cholinergic dysfunction contributes to gait disturbance in early Parkinson's disease  

PubMed Central

Gait disturbance is an early feature in Parkinson’s disease. Its pathophysiology is poorly understood; however, cholinergic dysfunction may be a non-dopaminergic contributor to gait. Short-latency afferent inhibition is a surrogate measure of cholinergic activity, allowing the contribution of cholinergic dysfunction to gait to be evaluated. We hypothesized that short-latency afferent inhibition would be an independent predictor of gait dysfunction in early Parkinson’s disease. Twenty-two participants with Parkinson’s disease and 22 age-matched control subjects took part in the study. Gait was measured objectively using an instrumented walkway (GAITRite), and subjects were asked to walk at their preferred speed for 2 min around a 25-m circuit. Spatiotemporal characteristics (speed, stride length, stride time and step width) and gait dynamics (variability described as the within subject standard deviation of: speed, stride time, stride length and step width) were determined. Short-latency afferent inhibition was measured by conditioning motor evoked potentials, elicited by transcranial magnetic stimulation of the motor cortex, with electrical stimuli delivered to the contralateral median nerve at intervals ranging from N20 (predetermined) to N20 + 4 ms. Short-latency afferent inhibition was determined as the percentage difference between test and conditioned response for all intervals and was described as the group mean. Participants were optimally medicated at the time of testing. Participants with Parkinson’s disease had significantly reduced gait speed (P = 0.002), stride length (P = 0.008) and stride time standard deviation (P = 0.001). Short-latency afferent inhibition was also significantly reduced in participants with Parkinson’s disease (P = 0.004). In participants with Parkinson’s disease, but not control subjects, significant associations were found between gait speed, short-latency afferent inhibition, age and postural instability and gait disorder score (Movement Disorders Society Unified Parkinson’s Disease Rating Scale) and attention, whereas global cognition and depression were marginally significant. No other gait variables were associated with short-latency afferent inhibition. A multiple hierarchical regression model explored the contribution of short-latency afferent inhibition to gait speed, controlling for age, posture and gait symptoms (Postural Instability and Gait Disorder score—Movement Disorders Society Unified Parkinson’s Disease Rating Scale), attention and depression. Regression analysis in participants with Parkinson’s disease showed that reduced short-latency afferent inhibition was an independent predictor of slower gait speed, explaining 37% of variability. The final model explained 72% of variability in gait speed with only short-latency afferent inhibition and attention emerging as independent determinants. The results suggest that cholinergic dysfunction may be an important and early contributor to gait dysfunction in Parkinson’s disease. The findings also point to the contribution of non-motor mechanisms to gait dysfunction. Our study provides new insights into underlying mechanisms of non-dopaminergic gait dysfunction, and may help to direct future therapeutic approaches.

Yarnall, Alison J.; Baker, Mark R.; David, Rachel V.; Lord, Susan; Galna, Brook; Burn, David J.

2012-01-01

316

Cholinergic dysfunction contributes to gait disturbance in early Parkinson's disease.  

PubMed

Gait disturbance is an early feature in Parkinson's disease. Its pathophysiology is poorly understood; however, cholinergic dysfunction may be a non-dopaminergic contributor to gait. Short-latency afferent inhibition is a surrogate measure of cholinergic activity, allowing the contribution of cholinergic dysfunction to gait to be evaluated. We hypothesized that short-latency afferent inhibition would be an independent predictor of gait dysfunction in early Parkinson's disease. Twenty-two participants with Parkinson's disease and 22 age-matched control subjects took part in the study. Gait was measured objectively using an instrumented walkway (GAITRite), and subjects were asked to walk at their preferred speed for 2 min around a 25-m circuit. Spatiotemporal characteristics (speed, stride length, stride time and step width) and gait dynamics (variability described as the within subject standard deviation of: speed, stride time, stride length and step width) were determined. Short-latency afferent inhibition was measured by conditioning motor evoked potentials, elicited by transcranial magnetic stimulation of the motor cortex, with electrical stimuli delivered to the contralateral median nerve at intervals ranging from N20 (predetermined) to N20 + 4 ms. Short-latency afferent inhibition was determined as the percentage difference between test and conditioned response for all intervals and was described as the group mean. Participants were optimally medicated at the time of testing. Participants with Parkinson's disease had significantly reduced gait speed (P = 0.002), stride length (P = 0.008) and stride time standard deviation (P = 0.001). Short-latency afferent inhibition was also significantly reduced in participants with Parkinson's disease (P = 0.004). In participants with Parkinson's disease, but not control subjects, significant associations were found between gait speed, short-latency afferent inhibition, age and postural instability and gait disorder score (Movement Disorders Society Unified Parkinson's Disease Rating Scale) and attention, whereas global cognition and depression were marginally significant. No other gait variables were associated with short-latency afferent inhibition. A multiple hierarchical regression model explored the contribution of short-latency afferent inhibition to gait speed, controlling for age, posture and gait symptoms (Postural Instability and Gait Disorder score-Movement Disorders Society Unified Parkinson's Disease Rating Scale), attention and depression. Regression analysis in participants with Parkinson's disease showed that reduced short-latency afferent inhibition was an independent predictor of slower gait speed, explaining 37% of variability. The final model explained 72% of variability in gait speed with only short-latency afferent inhibition and attention emerging as independent determinants. The results suggest that cholinergic dysfunction may be an important and early contributor to gait dysfunction in Parkinson's disease. The findings also point to the contribution of non-motor mechanisms to gait dysfunction. Our study provides new insights into underlying mechanisms of non-dopaminergic gait dysfunction, and may help to direct future therapeutic approaches. PMID:22961550

Rochester, Lynn; Yarnall, Alison J; Baker, Mark R; David, Rachel V; Lord, Susan; Galna, Brook; Burn, David J

2012-09-01

317

Depressive Symptoms and Gait Dysfunction in the Elderly  

PubMed Central

Objective Assess the association between depressive symptoms (not meeting the criteria for major depression) and gait dysfunction in older adults. Design Cross-sectional study. Setting Einstein Aging Study, a community-based longitudinal aging study. Participants Six hundred ten nondemented and nondepressed community-residing adults age 70 and older. Measurements Depressive symptoms measured using the 15-item Geriatric Depression Scale. To obtain a comprehensive assessment of gait, eight individual quantitative gait parameters were assessed: velocity (cm/s), stride length (cm), cadence (steps/min), swing phase (seconds), stance phase (seconds), double support phase (seconds), stride length variability (SD of stride length), and swing time variability (SD of swing time). Multiple linear regression analysis was applied to study the association of depressive symptoms with gait, adjusting for potential confounders including demographic variables, medical illnesses, and clinical gait abnormalities. Results Increased level of depressive symptoms was associated with worse velocity, stride, and swing time variability. The relationship of the remaining five gait variables with depressive symptoms was not significant in the fully adjusted models. Conclusions Higher levels of depressive symptoms are associated with worse performance in specific quantitative gait variables in community-residing older adults.

Brandler, Tamar C; Wang, Cuiling; Oh-Park, Mooyeon; Holtzer, Roee; Verghese, Joe

2011-01-01

318

Understanding gait control in post-stroke: implications for management.  

PubMed

The role of the brain in post-stroke gait is not understood properly, although the ability to walk becomes impaired in more than 80% of post-stroke patients. Most, however, regain some ability to walk with either limited mobility or inefficient, asymmetrical or unsafe gait. Conventional intervention focuses on support of weak muscles or body part by use of foot orthosis and walking aids. This review provides an overview of available evidence of neuro-kinesiology & neurophysiology of normal and post-stroke gait. The role of the spinal cord has been explored, more in animals than humans. Mammalian locomotion is based on a rhythmic, "pacemaker" activity of the spinal stepping generators. Bipedal human locomotion is different from quadripedal animal locomotion. However, knowledge derived from the spinal cord investigation of animals, is being applied for management of human gait dysfunction. The potential role of the brain is now recognized in the independent activation of muscles during walking. The brain modifies the gait pattern during the complex demands of daily activities. Though the exact role of the motor cortex in control of gait is unclear, available evidence may be applied to gait rehabilitation of post-stroke patients. PMID:22196422

Verma, Rajesh; Arya, Kamal Narayan; Sharma, Pawan; Garg, R K

2012-01-01

319

Gait generation and control in a climbing hexapod robot  

NASA Astrophysics Data System (ADS)

We discuss the gait generation and control architecture of a bioinspired climbing robot that presently climbs a variety of vertical surfaces, including carpet, cork and a growing range of stucco-like surfaces in the quasi-static regime. The initial version of the robot utilizes a collection of gaits (cyclic feed-forward motion patterns) to locomote over these surfaces, with each gait tuned for a specific surface and set of operating conditions. The need for more flexibility in gait specification (e.g., adjusting number of feet on the ground), more intricate shaping of workspace motions (e.g., shaping the details of the foot attachment and detachment trajectories), and the need to encode gait "transitions" (e.g., tripod to pentapod gait structure) has led us to separate this trajectory generation scheme into the functional composition of a phase assigning transformation of the "clock space" (the six dimensional torus) followed by a map from phase into leg joints that decouples the geometric details of a particular gait. This decomposition also supports the introduction of sensory feedback to allow recovery from unexpected event and to adapt to changing surface geometries.

Rizzi, A. A.; Haynes, G. C.; Full, R. J.; Koditschek, D. E.

2006-06-01

320

Video-Based Human Motion Estimation by Part-Whole Gait Manifold Learning  

Microsoft Academic Search

\\u000a This chapter presents a general gait representation framework for video-based human motion estimation that involves gait modeling\\u000a at both the whole and part levels. Our goal is to estimate the kinematics of an unknown gait from image sequences taken by\\u000a a single camera. This approach involves two generative models, called the kinematic gait generative model (KGGM) and the visual\\u000a gait

Guoliang Fan; Xin Zhang

321

Improvement of Freezing of Gait in Patients with Parkinson's Disease by Imagining Bicycling  

PubMed Central

Freezing of gait (FOG) is one of the factors that reduce the quality of life in patients with Parkinson's disease (PD). Imagining bicycling before gait start provided improvement in FOG in 2 PD patients. Imagining and mimicking bicycling after the initiation of gait allowed the rhythmic gait to continue without interruption. We suggest that imagining and mimicking bicycling, which are nonexternal cues, could serve as a helpful therapeutic approach for the intractable freezing and interruption of gait of PD patients.

Kikuchi, Akio; Baba, Toru; Hasegawa, Takafumi; Sugeno, Naoto; Konno, Masatoshi; Miura, Emiko; Oshima, Ryuji; Aoki, Masashi; Takeda, Atsushi

2014-01-01

322

When Does A Gait Transition Occur During Human Locomotion?  

PubMed Central

When a treadmill accelerates continuously, the walk-run transition has generally been assumed to occur at the instant when a flight phase is first observed, while the run-walk transition has been assumed to occur at the instant of the first double support period. There is no theoretical or empirical evidence to suggest that gait transitions occur at the instant of these events, nor even whether transitions are abrupt events. The purpose of this study was to determine whether the gait transitions during human locomotion occur abruptly, and if so, to determine the instant during a stride at which a transition occurs. The time history of the vertical velocity of the hip (vhip) and the angular velocity of the ankle (?ankle) were compared between constant speed strides (walking or running) and strides at and near the walk-run and run-walk transitions to determine if and when the transition strides resemble the stride of the corresponding constant speed strides. For both the walk-run and run-walk transitions, the stride prior to the transition resembled the original gait pattern, while the stride following the transition resembled the new gait pattern. The transition stride, however, did not resemble either a walking or a running stride during either of the transition directions. It was concluded that gait transitions are initiated at about midstance of the transition stride, but the transition is not completed until after an adjustment period of between one step and one stride. Thus, gait transitions are not abrupt events during human locomotion. Key pointsGait transitions are not abrupt events.Initiation of a gait transitions occur at about midstance of the transition stride.Gait transitions are completed approximately at the next heelstrike of the ipsilateral foot.Time period between initiation and completion of transition does not resemble either a walk or a run.

Hreljac, Alan; Imamura, Rodney T.; Escamilla, Rafael F.; Edwards, W. Brent

2007-01-01

323

Gait and menstrual cycle: ovulating women use sexier gaits and walk slowly ahead of men.  

PubMed

Previous research has demonstrated that women's physical appearance or sexual interest is different across the menstrual cycle. However, the nonverbal behavior of women toward men according to their menstrual cycle has not been previously explored. In this study, the gait of women walking ahead a male confederate was recorded with the help of a spy-camera. The amount of time that women spent walking was the first dependent variable whereas the extent to which the women were perceived to be sexually attractive by two judges was the second dependent variable. Comparisons were performed according to the women's ovulation phase measured with an LH salivary test. Near ovulation, it was found that women walked slower and their gait was subjectively rated as sexier. Such behaviors were interpreted as unconscious desires of women near ovulation to reinforce their attractiveness in order to attract more men and to increase their choice of a partner. PMID:22245227

Guéguen, Nicolas

2012-04-01

324

Wear performance of large-diameter differential-hardness hip bearings.  

PubMed

We hypothesized that differential-hardness hard-on-hard bearings would generate less wear debris compared with like-hardness metal-on-metal (M-o-M) bearings. We conducted wear testing on 3 types of large-diameter hard hip bearings: (1) contemporary cast-on-cast ("like" hardness) M-o-M; (2) differential-hardness M-o-M; and (3) differential-hardness ceramic-on-metal. A simulated gait profile ranging from 200 to 2000 N was applied to the bearings at a frequency of 1 Hz for 5 Mc. All bearings were tested in an anatomically inverted position in 90% alpha calf serum. Both differential-hardness bearing systems produced lower run-in wear rates (90%-97%), steady-state wear rate (45%-84%), and total metal wear (68%-88%) compared with the like-hardness bearing system. The ceramic-on-metal bearings exhibited the least wear followed by differential-hardness M-o-M bearings; like-hardness M-o-M bearings exhibited the greatest amount of wear. These findings support our hypothesis that differential-hardness hip bearing systems produce less metallic wear debris than those with like hardness and may result in lower metal ion release in vivo. PMID:18722303

Barnes, C Lowry; DeBoer, David; Corpe, R Scott; Nambu, Satya; Carroll, Michael; Timmerman, Irina

2008-09-01

325

Transverse plane gait problems in children with cerebral palsy.  

PubMed

Transverse plane deviations are significant contributors to pathologic gait in children with cerebral palsy (CP). Due to limitations in neuromuscular control, balance, strength and coordination, transverse plane gait deviations are poorly tolerated in these children. Transverse plane malalignment results in lever arm dysfunction and can be seen with either intoeing or out-toeing. Frequent causes of transverse plane problems and lever arm dysfunction include long bone (femoral and/or tibial) torsion, pelvic rotation, and pes varus or valgus. Computerized motion analysis facilitates accurate identification of transverse plane abnormalities. This article addresses appropriate identification and treatment of transverse plane gait deviations in children with CP. PMID:23653033

Rethlefsen, Susan A; Kay, Robert M

2013-06-01

326

Concurrent prediction of muscle and tibiofemoral contact forces during treadmill gait.  

PubMed

Detailed knowledge of knee kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. This study used publicly available data provided by the "Grand Challenge Competition to Predict in-vivo Knee Loads" for the 2013 American Society of Mechanical Engineers Summer Bioengineering Conference (Fregly et al., 2012, "Grand Challenge Competition to Predict in vivo Knee Loads," J. Orthop. Res., 30, pp. 503-513) to develop a full body, musculoskeletal model with subject specific right leg geometries that can concurrently predict muscle forces, ligament forces, and knee and ground contact forces. The model includes representation of foot/floor interactions and predicted tibiofemoral joint loads were compared to measured tibial loads for two different cycles of treadmill gait. The model used anthropometric data (height and weight) to scale the joint center locations and mass properties of a generic model and then used subject bone geometries to more accurately position the hip and ankle. The musculoskeletal model included 44 muscles on the right leg, and subject specific geometries were used to create a 12 degrees-of-freedom anatomical right knee that included both patellofemoral and tibiofemoral articulations. Tibiofemoral motion was constrained by deformable contacts defined between the tibial insert and femoral component geometries and by ligaments. Patellofemoral motion was constrained by contact between the patellar button and femoral component geometries and the patellar tendon. Shoe geometries were added to the feet, and shoe motion was constrained by contact between three shoe segments per foot and the treadmill surface. Six-axis springs constrained motion between the feet and shoe segments. Experimental motion capture data provided input to an inverse kinematics stage, and the final forward dynamics simulations tracked joint angle errors for the left leg and upper body and tracked muscle length errors for the right leg. The one cycle RMS errors between the predicted and measured tibia contact were 178?N and 168?N for the medial and lateral sides for the first gait cycle and 209?N and 228?N for the medial and lateral sides for the faster second gait cycle. One cycle RMS errors between predicted and measured ground reaction forces were 12?N, 13?N, and 65?N in the anterior-posterior, medial-lateral, and vertical directions for the first gait cycle and 43?N, 15?N, and 96?N in the anterior-posterior, medial-lateral, and vertical directions for the second gait cycle. PMID:24389997

Guess, Trent M; Stylianou, Antonis P; Kia, Mohammad

2014-02-01

327

Gait and Equilibrium in Subcortical Vascular Dementia  

PubMed Central

Subcortical vascular dementia is a clinical entity, widespread, even challenging to diagnose and correctly treat. Patients with this diagnosis are old, frail, often with concomitant pathologies, and therefore, with many drugs in therapy. We tried to diagnose and follow up for three years more than 600 patients. Study subjects were men and women, not bedridden, aged 68–94 years, outpatients, recruited from June, 1st 2007 to June, 1st 2010. We examined them clinically, neurologically, with specific consideration on drug therapies. Our aim has been to define gait and imbalance problem, if eventually coexistent with the pathology of white matter and/or with the worsening of the deterioration. Drug intake interference has been detected and considered.

Moretti, Rita; Torre, Paola; Antonello, Rodolfo M.; Esposito, Francesca; Bellini, Giuseppe

2011-01-01

328

Low Power Shoe Integrated Intelligent Wireless Gait Measurement System  

NASA Astrophysics Data System (ADS)

Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

2014-04-01

329

Interpolation function for approximating knee joint behavior in human gait  

NASA Astrophysics Data System (ADS)

Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

Toth-Ta?c?u, Mirela; Pater, Flavius; Stoia, Dan Ioan

2013-10-01

330

Causes of imbalance and abnormal gait that may be misdiagnosed.  

PubMed

Disorders of gait and balance are common in medicine and often lead to referral for neurologic evaluation. Because the maintenance of balance and normal gait are mediated by complex neurologic pathways as well as musculoskeletal, metabolic, and behavioral considerations, the list of possible contributing causes is very large. Much of the time, the history and neurologic examination reveal the underlying cause or causes. There are instances, however, when there are limited neurologic findings, as well as no structural abnormalities on brain or spine magnetic resonance imaging studies to explain the imbalance or gait difficulty. In this article, selected disorders that may be overlooked in the neurologic examination and imaging studies are reviewed. Possible causes of imbalance include occult drug-induced ataxia, autoimmune ataxia, ataxia associated with tremor, bilateral vestibular hypofunction, and spastic or dystonic gait disorders with normal imaging. PMID:24057830

Shill, Holly A; Fife, Terry D

2013-07-01

331

Virtual sensory feedback for gait improvement in neurological patients.  

PubMed

We review a treatment modality for movement disorders by sensory feedback. The natural closed-loop sensory-motor feedback system is imitated by a wearable virtual reality apparatus, employing body-mounted inertial sensors and responding dynamically to the patient's own motion. Clinical trials have shown a significant gait improvement in patients with Parkinson's disease using the apparatus. In contrast to open-loop devices, which impose constant-velocity visual cues in a "treadmill" fashion, or rhythmic auditory cues in a "metronome" fashion, requiring constant vigilance and attention strategies, and, in some cases, instigating freezing in Parkinson's patients, the closed-loop device improved gait parameters and eliminated freezing in most patients, without side effects. Patients with multiple sclerosis, previous stroke, senile gait, and cerebral palsy using the device also improved their balance and gait substantially. Training with the device has produced a residual improvement, suggesting virtual sensory feedback for the treatment of neurological movement disorders. PMID:24133478

Baram, Yoram

2013-01-01

332

Influence of acute anterior cruciate ligament deficiency in gait variability.  

PubMed

The objective of this study was to compare the gait variability of patients with isolated anterior cruciate ligament (ACL) deficiency (experimental group) with that of healthy individuals (control group). The hypothesis was that the gait variability of the experimental group would be higher than the control group. The experimental group consisted of 20 men with an ACL tear and the control group consisted of 20 healthy men without any neurological and/or musculoskeletal pathology or injury. The gait acceleration signal was analysed using the Gait Evaluation Differential Entropy Method (GEDEM). The GEDEM index of the experimental group in the medio-lateral axis was significantly higher than that of the control subjects. A receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of the method and to determine a cut-off entropy value. The GEDEM cut-off value had a 95.6% probability of separating isolated ACL patients from healthy subjects. PMID:20515565

Tzagarakis, G N; Tsivgoulis, S D; Papagelopoulos, P J; Mastrokalos, D S; Papadakis, N C; Kampanis, N A; Kontakis, G M; Nikolaou, P K; Katonis, P G

2010-01-01

333

Detection of freezing of gait in Parkinson disease: preliminary results.  

PubMed

Freezing of gait (FOG) is a common symptom in Parkinsonism, which affects the gait pattern and is associated to a fall risk. Automatized FOG episode detection would allow systematic assessment of patient state and objective evaluation of the clinical effects of treatments. Techniques have been proposed in the literature to identify FOG episodes based on the frequency properties of inertial sensor signals. Our objective here is to adapt and extend these FOG detectors in order to include other associated gait pattern changes, like festination. The proposed approach is based on a single wireless inertial sensor placed on the patient's lower limbs. The preliminary experimental results show that existing frequency-based freezing detectors are not sufficient to detect all FOG and festination episodes and that the observation of some gait parameters such as stride length and cadence are valuable inputs to anticipate the occurrence of upcoming FOG events. PMID:24740014

Coste, Christine Azevedo; Sijobert, Benoît; Pissard-Gibollet, Roger; Pasquier, Maud; Espiau, Bernard; Geny, Christian

2014-01-01

334

Detection of Freezing of Gait in Parkinson Disease: Preliminary Results  

PubMed Central

Freezing of gait (FOG) is a common symptom in Parkinsonism, which affects the gait pattern and is associated to a fall risk. Automatized FOG episode detection would allow systematic assessment of patient state and objective evaluation of the clinical effects of treatments. Techniques have been proposed in the literature to identify FOG episodes based on the frequency properties of inertial sensor signals. Our objective here is to adapt and extend these FOG detectors in order to include other associated gait pattern changes, like festination. The proposed approach is based on a single wireless inertial sensor placed on the patient's lower limbs. The preliminary experimental results show that existing frequency-based freezing detectors are not sufficient to detect all FOG and festination episodes and that the observation of some gait parameters such as stride length and cadence are valuable inputs to anticipate the occurrence of upcoming FOG events.

Coste, Christine Azevedo; Sijobert, Benoit; Pissard-Gibollet, Roger; Pasquier, Maud; Espiau, Bernard; Geny, Christian

2014-01-01

335

Gait recognition under carrying condition: a static dynamic fusion method  

NASA Astrophysics Data System (ADS)

When an individual carries an object, such as a briefcase, conventional gait recognition algorithms based on average silhouette/Gait Energy Image (GEI) do not always perform well as the object carried may have the potential of being mistakenly regarded as a part of the human body. To solve such a problem, in this paper, instead of directly applying GEI to represent the gait information, we propose a novel dynamic feature template for classification. Based on this extracted dynamic information and some static feature templates (i.e., head part and trunk part), we cast gait recognition on the large USF (University of South Florida) database by adopting a static/dynamic fusion strategy. For the experiments involving carrying condition covariate, significant improvements are achieved when compared with other classic algorithms.

Yu, Guan; Li, Chang-Tsun; Hu, Yongjian

2012-05-01

336

Development Aspects of a Robotised Gait Trainer for Neurological Rehabilitation.  

National Technical Information Service (NTIS)

The restoration of gait is a key goal after stroke, traumatic brain injury and spinal cord injury. Conventional training methods, e.g. treadmill training, require great physical effort from the therapists to assist the patient After the successful develop...

H. Schmidt D. Sorowka S. Hesse R. Bernhardt

2001-01-01

337

Active Magnetic Bearings.  

National Technical Information Service (NTIS)

The paper deals with a nonconventional type of bearing that is active magnetic bearing (AMB). Rotor suspension in AMB is achieved by attractive forces of electromagnetic poles. To stabilize the rotor position, the automatic control system is introduced. T...

Y. N. Zhuravlyov

1992-01-01

338

High Efficiency Magnetic Bearings.  

National Technical Information Service (NTIS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, param...

P. A. Studer C. P. Jayaraman D. K. Anand J. A. Kirk

1993-01-01

339

Shielded Bearing Lubrication.  

National Technical Information Service (NTIS)

Precise quantities of lubricant under automatic control are injected through chambers of housings into shielded rolling element bearings. Separate feed line conduits directly deliver the lubricant to the shielded critical surfaces of such bearings and ins...

J. A. Wong T. L. Daugherty G. D. Huntzberry

1996-01-01

340

Mechanical spin bearings  

NASA Technical Reports Server (NTRS)

A spin bearing assembly including, a pair of mutually opposing complementary bearing support members having mutually spaced apart bearing support surfaces which may be, for example, bearing races and a set of spin bearings located therebetween. Each spin bearing includes a pair of end faces, a central rotational axis passing through the end faces, a waist region substantially mid-way between the end faces and having a first thickness dimension, and discrete side surface regions located between the waist region and the end faces and having a second thickness dimension different from the first thickness dimension of the waist region and wherein the side surface regions further have respective curvilinear contact surfaces adapted to provide a plurality of bearing contact points on the bearing support members.

Vranish, John M. (Inventor)

1998-01-01

341

Axial Halbach Magnetic Bearings  

NASA Technical Reports Server (NTRS)

Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

2008-01-01

342

Polar Bears Change Diet  

NSDL National Science Digital Library

This radio broadcast from 2001 explains how polar bears have adjusted their diet due to the climate warming around Hudson Bay, Canada. The ringed seals that polar bears normally eat have been harder for polar bears to get to, due to disappearing ice. This has forced polar bears to begin eating harbor seals and bearded seals. The clip is 4 minutes and 15 seconds in length.

Schneider, Doug

2007-12-12

343

Data management in gait analysis for clinical applications  

Microsoft Academic Search

Objective. To study the reliability of gait analysis data obtained using the Calibrated Anatomical System Technique (cast) protocol and to verify the suitability and repeatability of the extraction of a number of parameters from the waveforms obtained.Design. The experimental protocol and the parametric analysis technique were applied on a population of able-bodied subjects.Background. The clinical interpretation process of gait data

MG Benedetti; F Catani; A Leardini; E Pignotti; S Giannini

1998-01-01

344

Human gait measurement based on rigid body and virtual markers  

Microsoft Academic Search

It is a key technique for the human gait measurement to enhance the precision and stability of human movement data collection. Human body was recognized as a 12-rigid-body structure (right\\/left upper arm, forearm, thigh, calf, foot and upper trunk, pelvis) according to human body anatomical pattern and normal gait characteristics. The technical difficulties often met during human movement capture measuring

Shanghai Jiao Tong; Wang Hong-sheng; Bai Xue-ling; Zhang Xi-an; Wang Cheng-tao

2008-01-01

345

Risk factors for freezing of gait in Parkinson's disease.  

PubMed

Freezing of gait is an episodic gait disorder that may occur in patients with Parkinson's disease. The risk factors for this disorder are poorly understood. To determine the relevant risk factors for this condition, we screened 160 consecutive patients with Parkinson's disease for freezing of gait and assessed 36 potentially related variables. Freezers and non-freezers were compared using statistical univariate analysis, followed by bivariate and multivariate logistic regression, receiver operating characteristics curves and Kaplan-Meier estimates. Seventy-one patients (44.4%) reported freezing of gait. At onset, the mean disease duration was 8.1±6.3years. Freezers experienced falls more frequently than non-freezers (57.7% vs 23.6%, p<0.001). Disease duration was the independent variable most associated with freezing of gait (OR=1.10, 95% CI=1.01-1.19, p=0.020). Its specificity was 77%, but its sensitivity was low, and Hoehn and Yahr staging and the UPDRS (part III) score showed similar accuracy to that of disease duration in predicting freezers. Previous antiparkinsonian treatments and predominant motor signs (tremor/akinesia-rigidity subtypes) at the onset of Parkinson's disease were not related to freezing of gait. Patients who developed Parkinson's disease before the age of 60years experienced freezing of gait earlier than older patients (log-rank, p<0.005). Freezing of gait is a common and disabling motor complication of Parkinson's disease that is related to the progression of the disease. It is not primarily associated with dopamine replacement therapy and may occur early in young patients. PMID:22795382

Contreras, Ana; Grandas, Francisco

2012-09-15

346

Ambient assessment of daily activity and gait velocity  

Microsoft Academic Search

This paper describes novel ambient technologies for domestic gait velocity measurement and in-home daily activity monitoring. This was achieved through low cost, easily deployable passive infrared motion detectors and an unobtrusive wireless sensor network. This system was deployed in the houses of eight older adults (1 faller; 7 non-fallers) living independently over eight weeks. Inter-daily gait velocity and daily activity

Lorcan Walsh; Barry R. Greene; Adrian Burns; Cliodhna Ni Scanaill

2011-01-01

347

Appearance-Based Gait Recognition Using Independent Component Analysis  

Microsoft Academic Search

For human identification at distance (HID) applications, gait characteristics are hard to conceal and has the inherent merits\\u000a such as non-contact and unobtrusive. In this paper, a novel appearance-based method for automatic gait recognition is proposed\\u000a using independent component analysis (ICA). Principal component analysis (PCA) is performed on image sequences of all persons\\u000a to get the uncorrelated PC coefficients. Then,

Jimin Liang; Yan Chen; Haihong Hu; Heng Zhao

2006-01-01

348

How to achieve various gait patterns from single nominal  

Microsoft Academic Search

In this paper is presented an approach to achieving on-line modification of nominal biped gait without recomputing entire dynamics when steady motion is performed. Straight, dynamically balanced walk was used as a nominal gait, and applied modifications were speed-up and slow-down walk and turning left and right. It is shown that the disturbances caused by these modifications jeopardize dynamic stability,

Miomir Vukobratovic; Dejan Andric; Branislav Borovac

2004-01-01

349

Optimal Gait Synthesis of a Seven-Link Planar Biped  

Microsoft Academic Search

In this paper, we carry out the dynamics-based optimization of sagittal gait cycles of a planar seven-link biped using the Pontryagin maximum principle. Special attention is devoted to the double-support phase of the gait, during which the movement is subjected to severe limiting conditions. In particular, due to the fact that the biped moves as a closed kinematic chain, overactuation

Guy Bessonnet; Stéphane Chessé; Philippe Sardain

2004-01-01

350

Bringing the compass-gait bipedal walker to three dimensions  

Microsoft Academic Search

The planar compass-gait biped has been exten- sively studied in the dynamic walking community, motivated by the gravity-based pendular efficiencies of human walking. These results can be extended to three dimensions using controlled geometric reduction for open-chain robots, by which stable 3- D walking gaits are built from known sagittal-plane limit cycles. We apply this method to the standard and

Robert D. Gregg; Mark W. Spong

2009-01-01

351

Tracking Polar Bears  

USGS Multimedia Gallery

Movements of 9 satellite-collared adult female polar bears were tracked in February, 2010 by satellite telemetry. Bears were collared in 2007, 2008, and 2009 on the spring-time sea ice of the southern Beaufort Sea or on the autumn pack ice in 2009. Polar bear satellite telemetry data are shown with ...

2010-04-13

352

Gait strategy in genetically obese patients: A 7-year follow up.  

PubMed

The aim of this study was to quantitatively evaluate the change in gait and body weight in the long term in patients with Prader-Willi Syndrome (PWS). Eight adults with PWS were evaluated at baseline and after 7 years. During this period patient participated an in- and out-patient rehabilitation programs including nutritional and adapted physical activity interventions. Two different control groups were included: the first group included 14 non-genetically obese patients (OCG: obese control group) and the second group included 10 age-matched healthy individuals (HCG: healthy control group). All groups were quantitatively assessed during walking with 3D-GA. The results at the 7-year follow-up revealed significant weight loss in the PWS group and spatial-temporal changes in gait parameters (velocity, step length and cadence). With regard to the hip joint, there were significant changes in terms of hip position, which is less flexed. Knee flexion-extension showed a reduction of flexion in swing phase and of its excursion. No changes of the ankle position were evident. As for ankle kinetics, we observed in the second session higher values for the peak of ankle power in terminal stance in comparison to the first session. No changes were found in terms of ankle kinetics. The findings demonstrated improvements associated to long-term weight loss, especially in terms of spatial-temporal parameters and at hip level. Our results back the call for early weight loss interventions during childhood, which would allow the development of motor patterns under normal body weight conditions. PMID:24763375

Cimolin, V; Vismara, L; Galli, M; Grugni, G; Cau, N; Capodaglio, P

2014-07-01

353

Automatic identification of gait events using an instrumented sock  

PubMed Central

Background Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance.

2011-01-01

354

Continuous curve registration as an intertrial gait variability reduction technique.  

PubMed

Timing in peak values shifts slightly between gait trials. When gait data are averaged, part of the standard deviation could be associated with this intertrial variability unless normalization is carried out beforehand. The objective of this study was to determine how continuous curve registration, an alignment technique, can reduce intersubject variability in gait data without altering the original curve characteristics. Gait data were obtained by means of a four-camera high-speed video system synchronized to a force plate. The data for 60 gait trials were collected from 20 young, healthy subjects. Curve registration was applied to hip angular displacement, net moment, and power curves generated in the sagittal plane. Following registration, the peak values increased by an average of 1.2% (0.11 +/- 0.26 degrees) for angular displacement, and by 11.2% (0.11 +/- 0.09 W/kg) for power, while there were no changes for moments. First and second derivatives of the unregistered and registered curves did not display significant differences, and the harmonics were barely affected. Continuous curve registration would thus be an appropriate technique for application prior to any statistical analysis using able-bodied gait patterns. PMID:12797722

Sadeghi, Heydar; Mathieu, Pierre A; Sadeghi, Somayeh; Labelle, Hubert

2003-03-01

355

Gait component changes observed during independent ambulation in young children.  

PubMed

The components of gait of the new independent ambulator can differ from that of the more experienced ambulator. The purposes of this review were to describe observable gait components exhibited at the onset of independent ambulation, the progression of changes in these components, and the time when a more mature pattern should be present consistently. Cross-sectional, longitudinal and single-recording studies, which analyzed children's gait at the onset of independent ambulation and followed changes in the components, were reviewed. Only components that can be observed by clinicians were included. The changes were reported as a function of time after independent ambulation onset or chronological age. The gait components evolved from (1) initial contact with toes, footflat or heel to consistent heel strike 1 y after independent ambulation onset or by 2.5 y of age, (2) a wide base of support to a narrower one 11 mo after independent ambulation onset or by 22 mo of age, and (3) upper extremities held in high guard position to reciprocal arm swing 11 mo after independent ambulation onset or by 3.5 y of age. Other components, such as the maintenance of squatted position and trunk flexion, were studied less extensively, but general descriptions are included. This review provides the length of time after independent ambulation onset or chronological age when the more mature form of a gait component should be present. The continued exhibition of a less mature form beyond these times may be indicative of a pathological gait pattern. PMID:23271309

Sala, Debra A; Cohen, Efrat

2013-05-01

356

Gait Patterns in Hemiplegic Patients with Equinus Foot Deformity  

PubMed Central

Equinus deformity of the foot is a common feature of hemiplegia, which impairs the gait pattern of patients. The aim of the present study was to explore the role of ankle-foot deformity in gait impairment. A hierarchical cluster analysis was used to classify the gait patterns of 49 chronic hemiplegic patients with equinus deformity of the foot, based on temporal-distance parameters and joint kinematic measures obtained by an innovative protocol for motion assessment in the sagittal, frontal, and transverse planes, synthesized by parametrical analysis. Cluster analysis identified five subgroups of patients with homogenous levels of dysfunction during gait. Specific joint kinematic abnormalities were found, according to the speed of progression in each cluster. Patients with faster walking were those with less ankle-foot complex impairment or with reduced range of motion of ankle-foot complex, that is with a stiff ankle-foot complex. Slow walking was typical of patients with ankle-foot complex instability (i.e., larger motion in all the planes), severe equinus and hip internal rotation pattern, and patients with hip external rotation pattern. Clustering of gait patterns in these patients is helpful for a better understanding of dysfunction during gait and delivering more targeted treatment.

Manca, M.; Ferraresi, G.; Cosma, M.; Cavazzuti, L.; Morelli, M.; Benedetti, M. G.

2014-01-01

357

Self-calibrating view-invariant gait biometrics.  

PubMed

We present a new method for viewpoint independent gait biometrics. The system relies on a single camera, does not require camera calibration, and works with a wide range of camera views. This is achieved by a formulation where the gait is self-calibrating. These properties make the proposed method particularly suitable for identification by gait, where the advantages of completely unobtrusiveness, remoteness, and covertness of the biometric system preclude the availability of camera information and specific walking directions. The approach has been assessed for feature extraction and recognition capabilities on the SOTON gait database and then evaluated on a multiview database to establish recognition capability with respect to view invariance. Moreover, tests on the multiview CASIA-B database, composed of more than 2270 video sequences with 65 different subjects walking freely along different walking directions, have been performed. The obtained results show that human identification by gait can be achieved without any knowledge of internal or external camera parameters with a mean correct classification rate of 73.6% across all views using purely dynamic gait features. The performance of the proposed method is particularly encouraging for application in surveillance scenarios. PMID:19884085

Goffredo, Michela; Bouchrika, Imed; Carter, John N; Nixon, Mark S

2010-08-01

358

Cryogenic Hybrid Magnetic Bearing  

NASA Technical Reports Server (NTRS)

Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

1994-01-01

359

Extraction of human gait signatures: an inverse kinematic approach using Groebner basis theory applied to gait cycle analysis  

NASA Astrophysics Data System (ADS)

This research highlights the results obtained from applying the method of inverse kinematics, using Groebner basis theory, to the human gait cycle to extract and identify lower extremity gait signatures. The increased threat from suicide bombers and the force protection issues of today have motivated a team at Air Force Institute of Technology (AFIT) to research pattern recognition in the human gait cycle. The purpose of this research is to identify gait signatures of human subjects and distinguish between subjects carrying a load to those subjects without a load. These signatures were investigated via a model of the lower extremities based on motion capture observations, in particular, foot placement and the joint angles for subjects affected by carrying extra load on the body. The human gait cycle was captured and analyzed using a developed toolkit consisting of an inverse kinematic motion model of the lower extremity and a graphical user interface. Hip, knee, and ankle angles were analyzed to identify gait angle variance and range of motion. Female subjects exhibited the most knee angle variance and produced a proportional correlation between knee flexion and load carriage.

Barki, Anum; Kendricks, Kimberly; Tuttle, Ronald F.; Bunker, David J.; Borel, Christoph C.

2013-05-01

360

In-home measurement of the effect of strategically weighted vests on ambulation.  

PubMed

Strategically weighted vests are currently being used to treat patients with Parkinson's, Multiple Sclerosis, and ataxia. While studies have been conducted to demonstrate the effectiveness of these vests, there has been very little research into the mechanisms that give rise to the vest's results. This study demonstrates the ability to capture gait parameters from depth images[1] in the home with sufficient sensitivity to support future investigation of the weighted vest intervention. The study also explores multiple metrics, using in-home gait sensing, to study a subject's ambulatory ability including gait mechanics, uncertainty in motion, and gait cadence. We then investigate the effects of these vests on a subject's ambulation by examining these metrics both before and after the vest is worn. While only four subjects were used, results are promising, showing a statistically significant and clinically significant change in many of these metrics as a result of the vest. The cases presented here concern two subjects, one with a "tight" gait caused by Progressive Supranuclear Palsy, and the second with an excessively "loose" gait due to Parkinson's disease. We show that in both subjects, using the vest immediately moved the metrics in a direction beneficial to the subject's clinical condition. This result concurs with clinical observations as measured using various clinical fall risk instruments. PMID:24109846

Wallace, Robert; Abbott, Carmen; Gibson-Horn, Cynthia; Skubic, Marjorie

2013-01-01

361

Quantitative Gait Analysis Detects Significant Differences in Movement between Osteoarthritic and Nonosteoarthritic Guinea Pig Strains before and after Treatment with Flunixin Meglumine  

PubMed Central

A computer-aided gait analysis system was used to contrast two guinea pig strains with differing propensity for osteoarthritis (OA), with/without administration of a nonsteroidal anti-inflammatory drug. Walking speed and static/dynamic gait parameters were determined at baseline. Flunixin meglumine was given and animals were evaluated 4, 24, and 72 hours after treatment. Body weight was compared using unpaired t-tests. Knee joints were histologically evaluated using species-specific criteria; indices were analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn's multiple comparisons. A generalized linear model followed by Tukey's posttests juxtaposed gait parameters; walking speed was a covariate for other outcome measures. Body weight was not different between strains; OA-prone animals demonstrated more progressive chondropathy. At baseline, OA-prone animals had slower walking speeds, narrower hind limb bases of support, shorter stride lengths, and slower limb swing speeds relative to OA-resistant animals. These differences were not detected 4 or 24 hours after treatment. By 72 hours, OA-prone animals had returned to baseline values. These findings indicate a distinct voluntary gait pattern in a rodent model of bilateral primary OA, modification of which may allow rapid screening of novel therapies. Flunixin meglumine temporarily permitted OA-prone animals to move in a manner that was analogous to OA-resistant animals.

Santangelo, K. S.; Kaeding, A. C.; Baker, S. A.; Bertone, A. L.

2014-01-01

362

Muscle contributions to vertical and fore-aft accelerations are altered in subjects with crouch gait  

PubMed Central

The goals of this study were to determine if the muscle contributions to vertical and fore-aft acceleration of the mass center differ between crouch gait and unimpaired gait and if these muscle contributions change with crouch severity. Examining muscle contributions to mass center acceleration provides insight into the roles of individual muscles during gait and can provide guidance for treatment planning. We calculated vertical and fore-aft accelerations using musculoskeletal simulations of typically-developing children and children with cerebral palsy and crouch gait. Analysis of these simulations revealed that during unimpaired gait the quadriceps produce large upward and backward accelerations during early stance, whereas the ankle plantarflexors produce large upward and forward accelerations later in stance. In contrast, during crouch gait, the quadriceps and ankle plantarflexors produce large, opposing fore-aft accelerations throughout stance. The quadriceps force required to accelerate the mass center upward was significantly larger in crouch gait than in unimpaired gait and increased with crouch severity. The gluteus medius accelerated the mass center upward during midstance in unimpaired gait; however, during crouch gait the upward acceleration produced by the gluteus medius was significantly reduced. During unimpaired gait the quadriceps and ankle plantarflexors accelerate the mass center at different times, efficiently modulating fore-aft accelerations. However, during crouch gait, the quadriceps and ankle plantarflexors produce fore-aft accelerations at the same time and the opposing fore-aft accelerations generated by these muscles contribute to the inefficiency of crouch gait.

Steele, Katherine M.; Seth, Ajay; Hicks, Jennifer L.; Schwartz, Michael H.; Delp, Scott L.

2012-01-01

363

Prediction of gait recovery in spinal cord injured individuals trained with robotic gait orthosis  

PubMed Central

Background Motor impairment is a major consequence of spinal cord injury (SCI). Earlier studies have shown that robotic gait orthosis (e.g., Lokomat) can improve an SCI individual’s walking capacity. However, little is known about the differential responses among different individuals with SCI. The present longitudinal study sought to characterize the distinct recovery patterns of gait impairment for SCI subjects receiving Lokomat training, and to identify significant predictors for these patterns. Methods Forty SCI subjects with spastic hypertonia at their ankles were randomly allocated to either control or intervention groups. Subjects in the intervention group participated in twelve 1-hour Lokomat trainings over one month, while control subjects received no interventions. Walking capacity was evaluated in terms of walking speed, functional mobility, and endurance four times, i.e. baseline, 1, 2, and 4 weeks after training, using the 10-Meter-Walking, Timed-Up-and-Go, and 6-Minute-Walking tests. Growth Mixture Modeling, an analytical framework for stratifying subjects based on longitudinal changes, was used to classify subjects, based on their gait impairment recovery patterns, and to identify the effects of Lokomat training on these improvements. Results Two recovery classes (low and high walking capacity) were identified for each clinical evaluation from both the control and intervention groups. Subjects with initial high walking capacity (i.e. shorter Timed-Up-and-Go time, higher 10-Meter-Walking speed and longer 6-Minute-Walking distance) displayed significant improvements in speed and functional mobility (0.033 m/s/week and–0.41 s/week respectively); however no significant change in endurance was observed. Subjects with low walking capacity exhibited no significant improvement. The membership in these two classes—and thus prediction of the subject’s gait improvement trajectory over time—could be determined by the subject’s maximum voluntary torque at the ankle under both plantar-and dorsi-flexion contractions determined prior to any training. Conclusion Our findings demonstrate that subjects responded to Lokomat training non-uniformly, and should potentially be grouped based on their likely recovery patterns using objective criteria. Further, we found that the subject’s ankle torque can predict whether he/she would benefit most from Lokomat training prior to the therapy. These findings are clinically significant as they can help individualize therapeutic programs that maximize patient recovery while minimizing unnecessary efforts and costs.

2014-01-01

364

SIZE AND GROWTH PATTERNS OF THE YELLOWSTONE GRIZZLY BEAR  

Microsoft Academic Search

Weights and\\/or measurements of 151 grizzly bears (Ursus arctos) captured 261 times were recorded from 1975 to 1985. Males were consistently heavier than females within all age classes beginning at age 2. Mean weight for 65 adult males (5+ years old) was 192 kg and 135 kg for 63 adult females (5 + years old). Mean monthly weights by sex

BONNIE M. BLANCHARD

365

Improvements in Sleep Quality and Gait Speed After Cataract Surgery  

PubMed Central

Abstract Background Gait speed and sleep quality are health indices related to longevity and mortality. In the present study, we measured sleep quality, quality of life, gait speed, and visual acuity before and after cataract surgery to evaluate the efficacy of the procedure on systemic health. Methods The study was conducted on 155 patients (93 women; average age 74.8 years) undergoing cataract surgery with the implantation of a yellow soft acrylic lens. Patients were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the National Eye Institute Visual Function Questionnaire 25 (VFQ-25; vision-related quality of life) before and then 2 and 7 months after surgery. Four-meter gait speed was also determined. Results Of the 155 patients, 68 (43.9%) were classified as poor sleepers (PSQI>5.5) prior to surgery. Significant improvements were noted in sleep 2 months after surgery (p<0.05, paired t-test), but thereafter the improvements were not significant. Prior to surgery, 117 patients (77.0%) were classified as slow walkers (speed<1.0 meter/s). Gait speed increased significantly in these patients 2 months after surgery (p<0.001, paired t-test). Multiple regression analysis revealed significant correlations between the preoperative VFQ-25 score and both PSQI (p<0.05) and gait speed (p<0.001). Postoperative increases in the VFQ-25 score were positively correlated with decreases in the PSQI (p<0.05). Improvements in visual acuity were correlated with improvements in the VFQ-25 score, but not with either PSQI or gait speed. Conclusion Cataract surgery effectively improves sleep quality and slow gait speed.

Muramatsu, Masahiro; Negishi, Kazuno; Tsubota, Kazuo

2013-01-01

366

Neural mechanisms involved in mental imagery and observation of gait.  

PubMed

Brain activity during observation and imagery of gait was investigated. Sixteen subjects were scanned with a 3-Tesla MRI scanner while viewing six types of video clips: observation of gait movement (GO) from the third-person perspective, observation of stepping movement, observation of standing posture, "virtual walking" (VW) that was observation of visual scenes mimicking the visual afferent during walking, and the scrambled version of the GO and VW stimuli. In the VW condition, moving scenes provided a virtual visual environment in which subjects easily imagined as if they were actually walking from the first-person perspective. A behavioral experiment revealed a correlation of cadence during actual walking with that during imaginary walking under the influence of the VW stimuli, indicating that a gait planning mechanism was shared by actual walking and gait imagery. The VW condition activated the dorsal premotor cortex (PMd), supplementary motor area/cingulate motor area (SMA/CMA), parahippocampal gyrus, and subcortical nuclei. The GO stimuli yielded activation of the SMA, PMd, inferior frontal gyrus, and inferior parietal lobule. Moreover, the conjunction null test of GO and VW revealed common activity in the SMA/CMA and PMd, which were reportedly active during actual gait movement, in addition to visual areas. Detailed analyses of activity during stepping or standing observation supported the specificity of the SMA and PMd to GO. These findings suggest that motor planning centers of gait, including the SMA and PMd, are activated during both imagination (first-person perspective) and observation (third-person perspective) of gait behaviors. PMID:18450480

Iseki, Kazumi; Hanakawa, Takashi; Shinozaki, Jun; Nankaku, Manabu; Fukuyama, Hidenao

2008-07-01

367

Two-dimensional PCA-based human gait identification  

NASA Astrophysics Data System (ADS)

It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

Chen, Jinyan; Wu, Rongteng

2012-11-01

368

Contributions to the understanding of gait control.  

PubMed

This thesis is based on ten published articles. The experimental work was carried out at the Faculty of Health Sciences, University of Copenhagen. The aim was to investigate and describe a number of basic mechanical and physiological mechanisms behind human walking. The methodologies used were biomechanical movement analysis and electrophysiology. The walking experiments were carried out in a gait lab, where the subjects were video recorded while they walked across two force platforms, which measured the ground reaction forces. Net joint moments about the hip-, knee- and ankle joint were calculated by combining the movement data and the external reaction forces (inverse dynamics). Muscle activity and sensory input to the spinal cord were measured by electromyography (EMG) and electrical stimulation of peripheral nerves. The results showed that the gait pattern varies to a great degree between individuals. Some people choose to exert the highest forces about the ankle joint while others prefer to use the knee joint. By use of a cluster analysis, fifteen healthy subjects could be divided into two groups. The extensor moment about the knee joint was the main factor for separating the two gait patterns, but the group with the highest extensor moments about the knee joint also walked with more flexed knee joints, higher EMG activity in the quadriceps muscle and higher bone-on-bone forces. This may lead to development of osteoarthritis over the years. Walking on high-heeled shoes reduced the ankle joint moment significantly either because of reduced muscle fiber length and/or increased co-contraction about the joint. On the contrary, the extensor moment about the knee joint was almost doubled in the high-heeled condition compared to bare footed walking at the same velocity. Also the EMG activity increased in the leg muscles. This could be an explanation pertaining to the higher incidence of osteoarthritis in women than in men. Patients with a drop-foot cannot put the foot to the ground with the heel first. Moreover, they have to increase flexion of the hip joint during the swing phase because the foot hangs in a plantar flexed position. It was shown that the ankle joint plantar flexor moment increased in the healthy leg and that the knee joint extensor moment increased significantly in both the affected and the healthy leg. The latter is most likely due to the patients trying to avoid an asymmetrical gait pattern. It is recommended to use an orthosis with drop-foot patients in order to keep the ankle joint dorsiflexed prior to touchdown, otherwise bone-on-bone forces in both knee joints will increase and probably lead to osteoarthritis. The hip joint moment varies less between individuals. However, both during walking and running an unexplained hip joint flexor moment is present during the last half of the stance phase. The moment appears to oppose the speed of progression and it has been suggested that it serves to balance the upper body. This was investigated in a group of healthy subjects who were asked to walk with their upper body in a reclined, inclined and normal position, respectively. It was shown that the hip joint flexor moment was similar in the reclined and the normal position but lower when walking in the inclined position and it can be concluded that the upper body is not balanced by hip joint flexor muscles but rather by accelerations of the pelvis and activity in abdominal and back muscles. These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. The gating of sensory input to th

Simonsen, Erik Bruun

2014-04-01

369

Classification of the Gait Patterns of Boys With Duchenne Muscular Dystrophy and Their Relationship to Function  

PubMed Central

Corticosteroids have recently been shown to reduce expected loss of muscle strength in patients with Duchenne muscular dystrophy and extend the time they can walk. We evaluated 43 boys with the condition to determine whether taking corticosteroids is associated with differences in gait pattern, gross motor skills, energy efficiency, and timed motor performance. We used the gait deviation index to quantify the degree of gait pathology and a single measure of gait quality. There were minimal differences in gait pattern, gross motor skills, energy efficiency, or timed motor performance in boys who took corticosteroids compared with those who did not. Clustering by gait deviation index, however, revealed subtle differences between groups in gait patterns, gross motor skills, and energy efficiency. We conclude that, in boys with Duchenne muscular dystrophy, gait pattern deviations are related to function, which can provide further insight into the understanding of disease progression and treatment options to enhance function and maintain ambulation.

Thomas, Susan Sienko; Buckon, Cathleen E.; Nicorici, Alina; Bagley, Anita; McDonald, Craig M.; Sussman, Michael D.

2013-01-01

370

Clumping Properties of Content-Bearing Words.  

ERIC Educational Resources Information Center

Defines the notion of serial clustering of words in text, and explores the value of such clustering as an indicator of a word's bearing content. This approach is flexible in the sense that it is context-sensitive; a numerical approach may also be of value in assigning weights to terms in requests. Experimental support is obtained from natural text…

Bookstein, A.; Klein, S. T.; Raita, T.

1998-01-01

371

Bearings: Technology and needs  

NASA Technical Reports Server (NTRS)

A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

Anderson, W. J.

1982-01-01

372

Effect of explicit visual feedback distortion on human gait  

PubMed Central

Background Gait rehabilitation often utilizes correction of stepping movements, and visual feedback is one of the interactive forms that can be used for rehabilitation. We presented a paradigm called visual feedback distortion in which we manipulated the visual representation of step length. Our previous work showed that an implicit distortion of visual feedback of step length entails unintentional modulations in the subjects’ gait spatial pattern. Even in the presence of cognitive load through a distraction task, distortion of visual feedback still induced modulation of gait step length. In the current study, subjects were aware of the imposed distortion of visual feedback and they were instructed to maintain their natural gait symmetric pattern during trials. We then studied whether such an explicit “visual feedback distortion” would still influence gait spatial pattern. Methods Nine healthy subjects participated in the treadmill walking trial. The step length was defined as the distance between each foot. The on-line visual feedback showing right and left step length information as bar graphs was displayed on a computer screen. When distorting the visual feedback, the height of the bar for only one side was manipulated, so that subjects perceived their step length as being asymmetric. Actual step lengths were measured during trial and analyzed to see the effects of visual feedback distortion. Results Our results showed that a gradual distortion of visual feedback systematically modulated gait step length away from symmetry even at the expense of an opposing apparent task goal. It was also observed that the amount of induced gait modulation was reduced during the explicit condition compared to the implicit condition where subjects were not aware of distortion. Conclusions Our study demonstrated that although the visual feedback display used in this study did not alter visual space or evoke illusions of motion, perturbation of visual information about subjects’ movement can cause unintentional motor functions. This suggests that the effect of visual feedback distortion is spontaneous and a gait training involving the visual distortion paradigm may provide an effective way to help subjects correct gait patterns by driving implicit motor functions, thereby bringing benefits to rehabilitation.

2014-01-01

373

Principal Component Analysis of gait in Parkinson's disease: relevance of gait velocity.  

PubMed

Principal Component Analysis (PCA) is a method to estimate the relation between data points. We used PCA to analyse movements of the upper and lower extremities during treadmill walking in healthy subjects and two groups of Parkinsonian patients. Healthy subjects (n=35) showed a typical pattern with high values of PC1 and low values in a descending order of PC2-PC4. Increase of speed resulted in a significant increase of PC1 and a significant decrease of the following PC's. In more severely affected patients (n=19, UPDRS>20), PC1 was significantly decreased and PC2-PC4 were significantly increased compared to healthy subjects. Speed could be increased only within a small range without corresponding changes of the PC's. In less severely affected patients (n=17), significant differences of the PC's were only found with fast pace. Separate analysis of arms and legs revealed that these changes are only due to altered movements of the arm. Analysis of the pattern of PC's in response to changes of gait velocities reveal alterations even in less severely affected Parkinsonian patients. The changes of the PC's with higher gait velocities in healthy subjects are suggestive of an increase of intersegmental coordination. This is impaired even in less severely affected Parkinsonian patients. PMID:24374062

Dillmann, Ulrich; Holzhoffer, Claudia; Johann, Yvonne; Bechtel, Sabrina; Gräber, Stefan; Massing, Christoph; Spiegel, Jörg; Behnke, Stefanie; Bürmann, Jan; Louis, Alfred K

2014-03-01

374

Gait-based gender classification using mixed conditional random field.  

PubMed

This paper proposes a supervised modeling approach for gait-based gender classification. Different from traditional temporal modeling methods, male and female gait traits are competitively learned by the addition of gender labels. Shape appearance and temporal dynamics of both genders are integrated into a sequential model called mixed conditional random field (CRF) (MCRF), which provides an open framework applicable to various spatiotemporal features. In this paper, for the spatial part, pyramids of fitting coefficients are used to generate the gait shape descriptors; for the temporal part, neighborhood-preserving embeddings are clustered to allocate the stance indexes over gait cycles. During these processes, we employ evaluation functions like the partition index and Xie and Beni's index to improve the feature sparseness. By fusion of shape descriptors and stance indexes, the MCRF is constructed in coordination with intra- and intergender temporary Markov properties. Analogous to the maximum likelihood decision used in hidden Markov models (HMMs), several classification strategies on the MCRF are discussed. We use CASIA (Data set B) and IRIP Gait Databases for the experiments. The results show the superior performance of the MCRF over HMMs and separately trained CRFs. PMID:21622075

Hu, Maodi; Wang, Yunhong; Zhang, Zhaoxiang; Zhang, De

2011-10-01

375

An adaptive gyroscope-based algorithm for temporal gait analysis.  

PubMed

Body-worn kinematic sensors have been widely proposed as the optimal solution for portable, low cost, ambulatory monitoring of gait. This study aims to evaluate an adaptive gyroscope-based algorithm for automated temporal gait analysis using body-worn wireless gyroscopes. Gyroscope data from nine healthy adult subjects performing four walks at four different speeds were then compared against data acquired simultaneously using two force plates and an optical motion capture system. Data from a poliomyelitis patient, exhibiting pathological gait walking with and without the aid of a crutch, were also compared to the force plate. Results show that the mean true error between the adaptive gyroscope algorithm and force plate was -4.5 ± 14.4 ms and 43.4 ± 6.0 ms for IC and TC points, respectively, in healthy subjects. Similarly, the mean true error when data from the polio patient were compared against the force plate was -75.61 ± 27.53 ms and 99.20 ± 46.00 ms for IC and TC points, respectively. A comparison of the present algorithm against temporal gait parameters derived from an optical motion analysis system showed good agreement for nine healthy subjects at four speeds. These results show that the algorithm reported here could constitute the basis of a robust, portable, low-cost system for ambulatory monitoring of gait. PMID:21042951

Greene, Barry R; McGrath, Denise; O'Neill, Ross; O'Donovan, Karol J; Burns, Adrian; Caulfield, Brian

2010-12-01

376

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis  

NASA Technical Reports Server (NTRS)

Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

Hausdorff, J. M.; Lertratanakul, A.; Cudkowicz, M. E.; Peterson, A. L.; Kaliton, D.; Goldberger, A. L.

2000-01-01

377

Secure and privacy enhanced gait authentication on smart phone.  

PubMed

Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

Hoang, Thang; Choi, Deokjai

2014-01-01

378

[Apraxia of gait and disorders in posture and locomotion].  

PubMed

Apraxia of gait is a unique disorder of locomotion characterized by inability in lifting the feet from the floor despite alternating stepping action (frozen gait), and disequilibrium. Responsible site of lesions are in the frontal lobe and/or the basal ganglia. It is observed in an advanced stage of Parkinson's (PD) or vascular parkinsonism with multiple cerebral infarction (MCI). Studies on equilibrium and natural gait have disclosed unique features in this condition. Records of floor reaction forces in forward locomotion showed that vertical-foreaft vector angles at kick-off phase is small in both PD and MCI with frozen gait. EMG of antagonists in leg muscles were either reciprocal or coincided in frozen gait, and rhythm of stepping was crucial for development of freezing. Center of foot pressure (CFP) in forward-bent natural posture in PD still locates behind that of normals. For voluntary forward bending, maximal shift of CFP was smaller, and increase in EMG was larger in PD subjects. Pushing chest backward results in step-out or fall in parkinsonians. In this response, EMG in the pretibial muscles were the same amount in both PD and normals. However, velocity in hip extension and amount of knee and ankle displacement were smaller in PD. PMID:8174333

Yanagisawa, N; Ueno, E; Hayashi, R; Tokuda, T; Takou, K

1993-12-01

379

Spinal cord stimulation for gait impairment in spinocerebellar ataxia 7.  

PubMed

The aim of this study is to report on the clinical efficacy of epidural thoracic spinal cord stimulation on gait and balance in a 39-year-old man with genetically confirmed spinocerebellar ataxia 7. A RESUME Medtronic electrode was placed at the epidural T11 level. Spatiotemporal gait assessment using an electronic walkway and static posturography were obtained and analyzed in a blinded manner with and without stimulation. The Tinetti Mobility Test was also performed in the two conditions. At 11 months after surgery, there was a 3-point improvement in the Tinetti Mobility Test in the on stimulation condition, although there was no statistically significant difference in spatiotemporal gait parameters. Static posturography did not demonstrate a significant improvement in stability measures between the two conditions in a stochastic way. Thoracic epidural spinal cord stimulation had a mild but clinically meaningful beneficial effect in improving gait and balance in a patient with SCA-7. The underlying pathophysiologic mechanisms remain to be elucidated. Further experience with spinal cord stimulation in refractory gait disorders is warranted. PMID:24390202

Sidiropoulos, Christos; Masani, Kei; Mestre, Tiago; Milosevic, Matija; Poon, Yu-Yan; Fallis, Melanie; Shah, Binit B; Kalia, Suneil K; Popovic, Milos R; Lozano, Andres M; Moro, Elena

2014-03-01

380

Robust Gait-Based Person Identification against Walking Speed Variations  

NASA Astrophysics Data System (ADS)

Variations in walking speed have a strong impact on gait-based person identification. We propose a method that is robust against walking-speed variations. It is based on a combination of cubic higher-order local auto-correlation (CHLAC), gait silhouette-based principal component analysis (GSP), and a statistical framework using hidden Markov models (HMMs). The CHLAC features capture the within-phase spatio-temporal characteristics of each individual, the GSP features retain more shape/phase information for better gait sequence alignment, and the HMMs classify the ID of each gait even when walking speed changes nonlinearly. We compared the performance of our method with other conventional methods using five different databases, SOTON, USF-NIST, CMU-MoBo, TokyoTech A and TokyoTech B. The proposed method was equal to or better than the others when the speed did not change greatly, and it was significantly better when the speed varied across and within a gait sequence.

Aqmar, Muhammad Rasyid; Shinoda, Koichi; Furui, Sadaoki

381

Secure and Privacy Enhanced Gait Authentication on Smart Phone  

PubMed Central

Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits.

Choi, Deokjai

2014-01-01

382

Bear Spray Safety Program  

USGS Publications Warehouse

A bear spray safety program for the U.S. Geological Survey (USGS) was officially initiated by the Firearms Safety Committee to address accident prevention and to promote personnel training in bear spray and its transportation, storage, and use for defense against wild animals. Used as part of a system including firearms, or used alone for those who choose not to carry a firearm, bear spray is recognized as an effective tool that can prevent injury in a wild animal attack.

Blome, C. D.; Kuzniar, R. L.

2009-01-01

383

The Incredible Water Bear  

NSDL National Science Digital Library

This image-rich Micscape Magazine article explores how water bears can be found almost everywhere yet are still unknown to almost everybody, why there are relatively few light microscope photographs of water bears in the literature and on the Web, and how light microscopy can outperform scanning electron microscopy when viewing these animals. It includes a list of historical references, early sketches, and colorful images of water bears, also known as tardigrades.

Mach, Martin; Magazine, Micscape

384

Intrasubject repeatability of gait analysis data in normal and spastic children  

Microsoft Academic Search

Objective. To evaluate intrasubject repeatability of data obtained from computer-aided motion analysis in normal and spastic children.Design. Prospective controlled study.Background. Information from gait analysis is used in selecting therapeutic interventions for gait improvement in cerebral palsy. While there are several studies regarding repeatability of normal gait, there are no studies evaluating the repeatability of spastic gait.Methods. Forty children (20 normal,

Gerhardt Steinwender; Vinay Saraph; Sabine Scheiber; Ernst Bernhard Zwick; Christiane Uitz; Karl Hackl

2000-01-01

385

Bearing restoration by grinding  

NASA Technical Reports Server (NTRS)

A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

1976-01-01

386

Early onset of stabilizing strategies for gait and obstacles: Older adults with Down syndrome  

PubMed Central

Our goal was to examine the gait patterns of older adults with Down syndrome (DS) for precocious stabilizing adaptations during comfortable over-ground walking and in more challenging conditions. Twelve participants with DS and 12 with typical development (TD) were matched for height, weight and age (range 35 to 62 years). We used a 6-camera motion capture system to assess foot trajectories over obstacles. Participants first walked at their preferred speed over a 5.3 m instrumented gait mat (unperturbed condition). Subsequent walking trials included perturbations mid-walkway: a) minimal obstacle to step over (12 cm high), b) moderate obstacle to step onto with both feet and then off (standard step), c) maximum obstacle to step onto with only one foot and over with the other (standard step). Adults with DS walked slower with shorter, wider strides while spending more time in both stance and double support. These adaptations increased during the moderate and maximal perturbations. They stepped with the minimal perturbation obstacle further forward in their crossing step and produced a lower, flatter trajectory of the lead foot, with less dorsiflexion at crossing. This strategy decreased trailing toe clearance but did not alter leading heel clearance. The combined effects of ligamentous laxity, low tone, obesity, inactivity and physiological decrements associated with aging lead to these stability-enhancing adaptations at a younger chronological age in adults with DS. We believe intervention to increase overall stability will be beneficial in helping adults with DS maintain optimal functional mobility and health.

Ulrich, Beverly D

2008-01-01

387

Quadrupedal Gait Generation Based on Human Feeling for Robot Assisted Therapy  

Microsoft Academic Search

In the field of pet robots and robot assisted therapy (RAT), animal motion is important for robots resembling various animals. This paper presents a method for the generation of animal gait in quadrupedal robots. In this study, we employ AIBO as an experimental quadrupedal robot and generate the AIBO's gait on the basis of an animal's gait. First, we optimize

Hidekazu Suzuki; Hitoshi Nishi

2008-01-01

388

Kinematic analysis of the gait of 10 labrador retrievers during treadmill locomotion  

Microsoft Academic Search

The trotting gait of 10 sound, adult labrador retrievers was analysed using kinematic gait analysis on a purpose-built treadmill using video-based motion analysis software. The maximal angular displacement, minimal angular displacement, average angular displacement, and the maximal positive and negative angular velocities of the right elbow and right stifle were measured over five gait cycles at defined time points during

D. N. Clements; M. R. Owen; S. Carmichael; S. W. J. Reid

2005-01-01

389

Nonconsecutive versus consecutive footstrikes as an equivalent method of assessing gait asymmetry  

Microsoft Academic Search

Asymmetry of gait is often studied to characterize populations and assess the efficacy of treatment protocols. However, despite the continuous nature of gait, many studies have made comparisons between data from non-consecutive footstrikes. This is typically considered a limitation of these studies. However, if gait characteristics are sufficiently repeatable within a side, consecutive footstrikes may not be necessary to properly

Rebecca Avrin Zifchock; Irene Davis

2008-01-01

390

Performance analysis for automated gait extraction and recognition in multi-camera surveillance  

Microsoft Academic Search

Many studies have confirmed that gait analysis can be used as a new bio- metrics. In this research, gait analysis is deployed for people identification in multi- camera surveillance scenarios. We present a new method for viewpoint independent markerless gait analysis that does not require camera calibration and works with a wide range of walking directions. These properties make the

Michela Goffredo; Imed Bouchrika; John N. Carter; Mark S. Nixon

2010-01-01

391

Computational Intelligence in Gait Research: A Perspective on Current Applications and Future Challenges  

Microsoft Academic Search

Our mobility is an important daily requirement so much so that any disruption to it severely degrades our perceived quality of life. Studies in gait and human movement sciences, there- fore, play a significant role in maintaining the well-being of our mobility. Current gait analysis involves numerous interdependent gait parameters that are difficult to adequately interpret due to the large

Daniel T. H. Lai; Rezaul K. Begg; Marimuthu Palaniswami

2009-01-01

392

Obstacle Avoidance of Snake Robot Moving with A Novel Gait Using Two-Level PID Controller  

Microsoft Academic Search

In this paper, we introduce a novel locomotion mode (gait) for 2D snake robots. The idea behind this new gait is to control orientation of snake robot by head link and use other links as a means of driving the robot. When snake robot moves using this gait, head link always looks at direction of motion and can therefore receive

Shahir Hasanzadeh; Ali Akbarzadeh Tootoonchi

2008-01-01

393

An analytical method on real-time gait planning for a humanoid robot  

Microsoft Academic Search

This paper studies the real-time gait planning for a humanoid robot. By simultaneously planning the trajectories of the COG (center of gravity) and the ZMP (zero moment point), the fast and smooth change of gait, can be realized. The change of gait is also realized by connecting the newly calculated trajectories to the current ones. While we propose two methods

Kensuke Harada; Shuuji Kajita; K. Kaneko; H. Hirukawa

2004-01-01

394

Natural Gait Generation Techniques for Multi-bodied Isolated Mechanical Systems  

Microsoft Academic Search

This paper investigates how to generate cyclic gaits for multi-bodied isolated mechanical systems whose configuration space is represented by a trivial fiber bundle. We describe how to generate gaits in the base space of the fiber bundle, or the shape space of the robot on which we assume full control. Such gaits are guaranteed to generate a non-zero motion along

Elie A. Shammas; Klaus Schmidt; Howie Choset

2005-01-01

395

Part-based human gait identification under clothing and carrying condition variations  

Microsoft Academic Search

Gait recognition has already achieved satisfactory performance on small databases under ideal conditions. Most of the existing approaches represent gait pattern using a locomotion model or statistic model of human silhouette. However, it is still a challenging task to conduct human gait identification under variations of clothing and carrying condition in real scenes. In this paper, an adaptive part-based feature

Ning Li; Yi Xu; Xiao-Kang Yang

2010-01-01

396

The effect of joint stiffness on simulation of the complete gait cycle  

Microsoft Academic Search

A computer simulation of paraplegic, walker assisted gait through multiple gait cycles is described. Computational problems associated with changing constraints during transitions between phases of gait are avoided by modeling foot-to-floor contact as an external force. Net joint torques, computed from kinematic data by inverse dynamics and transformed into sine functions, are used to drive limb motion. Model instability is

A. Scheiner; Donald C. Ferencz; Howard J. Chizeck

1994-01-01

397

Evaluation of an ambulatory system for gait analysis in hip osteoarthritis and after total hip replacement  

Microsoft Academic Search

Spatial and temporal parameters of gait have clinical relevance in the assessment of motor pathologies, particularly in orthopaedics. A new gait analysis system is proposed which consists of (a) an ambulatory device (Physilog®) including a set of miniature gyroscopes and a portable datalogger, and (b) an algorithm for gait analysis. The aim of this study was the validation of this

K Aminian; C Trevisan; B Najafi; H Dejnabadi; C Frigo; E Pavan; A Telonio; F Cerati; E. C Marinoni; Ph Robert; P.-F Leyvraz

2004-01-01

398

A Review of Balance and Gait Capacities in Relation to Falls in Persons with Intellectual Disability  

ERIC Educational Resources Information Center

Limitations in mobility are common in persons with intellectual disabilities (ID). As balance and gait capacities are key aspects of mobility, the prevalence of balance and gait problems is also expected to be high in this population. The objective of this study was to critically review the available literature on balance and gait characteristics…

Enkelaar, Lotte; Smulders, Ellen; van Schrojenstein Lantman-de Valk, Henny; Geurts, Alexander C. H.; Weerdesteyn, Vivian

2012-01-01

399

Classification of human gait features with different apparel and walking speed  

Microsoft Academic Search

In this paper, we proposed a new approach for the classification of human gait features with different apparel and various walking speed. The approach consists of two parts: extraction of human gait features from enhanced human silhouette and classification of the extracted human gait features using fuzzy k-nearest neighbours (KNN). The joint angles together with the height, width and crotch

Hu Ng; Hau-Lee Tong; Wooi-Haw Tan; J. Abdullah

2010-01-01

400

Biomechanical gait alterations independent of speed in the healthy elderly: Evidence for specific limiting impairments  

Microsoft Academic Search

Objectives: It is not known whether changes in the biomechanics of elderly gait are related to aging per se, or to reduced walking speed in this population. The goals of the present study were to identify specific biomechanical changes, independent of speed, that might impair gait performance in healthy older people by identifying age-associated changes in the biomechanics of gait,

D. Casey Kerrigan; Mary K. Todd; Ugo Della Croce; Lewis A. Lipsitz; James J. Collins

1998-01-01

401

The Effect of Bearing Deformation in Slider-bearing Lubrication  

Microsoft Academic Search

The slider-bearing with the bearing elastic is analyzed for its load carrying characteristics. The deflection of the bearing under load acts to reduce the load capacity by an amount which can be significant as is illustrated by a numerical example. Contributed by the ASLE Technical Committee on Bearings and Bearing Lubrication and presented at the Annual Meeting of the American

F. Osterle; Edward Saibel

1958-01-01

402

Diagnosing health problems from gait patterns of elderly.  

PubMed

A system for diagnosing health problems from gait patterns of elderly to support their independent living is proposed in this paper. Motion capture system, which consists of tags attached to the body and sensors situated in the apartment, is used to capture gait of elderly. Position of the tags is acquired by the sensors and the resulting time series of position coordinates are analyzed with machine learning algorithms in order to recognize the specific health problem. We propose novel features for training a machine learning classifier that classifies the user's gait into four health problems and a normal health state. Results showed that decision tree classifier was able to reach 95% of classification accuracy using 7 tags and 5 mm standard deviation of noise. Neural network outperformed it with classification accuracy over 99% using 8 tags with 0-20 mm noise. Control panel prototype has been developed to provide explanation of the automatic diagnosis. PMID:21096794

Pogorelc, Bogdan; Gams, Matjaz

2010-01-01

403

Extracting gait parameters from raw electronic walkway data.  

PubMed

Spatiotemporal gait parameters are very important for the detection of gait impairments and associated conditions. Current methods to measure such parameters, e.g. electronic walkways or force plates, are costly and can only be used in a laboratory. The new generation of raw data accelerometers might be a cheap and flexible alternative. We conducted a small feasibility study with 50 subjects from the KORA-Age project exploring the output of GAITRite and Actigraph GT3X. We open-sourced a package to extract and process raw data from GAITRite. The most promising location for the accelerometer seems to be at the ankle. The use of accelerometers showed to be simple and reliable, indicating that they can be used in daily life to extract gait parameters. PMID:21893789

Dias, André; Gorzelniak, Lukas; Döring, Angela; Hartvigsen, Gunnar; Horsch, Alexander

2011-01-01

404

Gait apraxia after bilateral supplementary motor area lesion  

PubMed Central

Objectives: The study aimed at addressing the issue of the precise nature of gait apraxia and the cerebral dysfunction responsible for it. Methods: The case of a patient, affected by a bilateral infarction limited to a portion of the anterior cerebral artery territory is reported. The patient's ability to walk was formally assessed by means of a new standardised test. Results: Due to an anomaly within the anterior cerebral artery system, the patient's lesion was centred on the supplementary motor regions of both hemispheres. He presented with clear signs of gait apraxia that could not be accounted for by paresis or other neurological deficits. No signs of any other form of apraxia were detected. Conclusions: The clinical profile of the patient and the analysis of 49 cases from previous literature suggest that gait apraxia should be considered a clinical entity in its own right and lesions to the supplementary motor areas are responsible for it.

Della, S; Francescani, A; Spinnler, H

2002-01-01

405

Subtle gait changes in patients with REM sleep behavior disorder.  

PubMed

Many people with rapid eye movement (REM) sleep behavior disorder (RBD) have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. Because gait disorders are common in the synucleinopathies, early abnormalities in gait in those with RBD could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. We identified 42 probable RBD subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence, and stride dynamics with an automated gait analysis system. Cases and controls were similar in age (79.9?±?4.7 and 80.1?±?4.7, P?=?0.74), Unified Parkinson's Disease Rating Scale Part III (UPDRS) score (3.3?±?5.5 and 1.9?±?4.1, P?=?0.21) and Mini-Mental State Examination scores (27.2?±?1.9 and 27.7?±?1.6, P?=?0.10). A diagnosis of probable RBD was associated with decreased velocity (-7.9 cm/s; 95% confidence interval [CI], -13.8 to -2.0; P?gait changes prior to overt clinical parkinsonism. Diagnosis of probable RBD supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

McDade, Eric M; Boot, Brendon P; Christianson, Teresa J H; Pankratz, V Shane; Boeve, Bradley F; Ferman, Tanis J; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S; Petersen, Ronald C

2013-11-01

406

Gait characteristics following Achilles tendon elongation: the foot rocker perspective.  

PubMed

The action of three functional rockers, namely the heel, ankle and forefoot rocker, assist the progression of the leg over the supporting foot. The purpose of this case series was to analyze the occurrence of foot rockers during gait in three children with cerebral palsy (CP) who had undergone the tendo-Achilles lengthening (TAL), procedure followed by a clinic- or home-based intervention and in one child with CP without history of surgery. Self-selected gait was video-recorded in a laboratory during six testing sessions at half-year intervals rendering a 3 year period of observation. One child had pre- and post-surgical gait data and the other two had post surgical data only. Sagittal plane knee angular velocity, as well as foot to ground positions, and foot rocker occurrence were analyzed. In a child with history of CP, and without history of surgery, mean angular velocities of the 1st, 2nd and 3rd foot rocker were 3.7, 0.57 and 6.67 rad/s, respectively, and the step length and cadence were normal. In children who underwent TAL the 1st and 2nd rocker was absent, as the initial contact of the foot with the ground was either with foot-flat or forefoot. The mean velocity of the 3rd rocker in children who underwent TAL was lower by approximately 50-80% than that of the nonsurgical case. Furthermore, the characteristic pattern of the knee joint to foot-floor position during gait was not observed in these cases. Foot rocker analysis identified children with abnormal gait characteristics. Following surgery these gait characteristics remained abnormal. PMID:18634352

Bober, Tadeusz; Dziuba, Alicja; Kobel-Buys, Krystyna; Kulig, Kornelia

2008-01-01

407

Inhibition, Executive Function, and Freezing of Gait  

PubMed Central

Background Studies suggest that freezing of gait (FoG) in people with Parkinson’s disease (PD) is associated with declines in executive function (EF). However, EF is multi-faceted, including three dissociable components: inhibiting prepotent responses, switching between task sets, and updating working memory. Objective This study investigated which aspect of EF is most strongly associated with FoG in PD. Method Three groups were studied: adults with PD (with and without FoG) and age-matched, healthy adults. All participants completed a battery of cognitive tasks previously shown to discriminate among the three EF components. Participants also completed a turning-in-place task that was scored for FoG by neurologists blind to subjects’ self-reported FoG. Results Compared to both other groups, participants with FoG showed significant performance deficits in tasks associated with inhibitory control, even after accounting for differences in disease severity, but no significant deficits in task-switching or updating working memory. Surprisingly, the strongest effect was an intermittent tendency of participants with FoG to hesitate, and thus miss the response window, on go trials in the Go-Nogo task. The FoG group also made slower responses in the conflict condition of the Stroop task. Physician-rated FoG scores were correlated both with failures to respond on go trials and with failures to inhibit responses on nogo trials in the Go-Nogo task. Conclusion These results suggest that FoG is associated with a specific inability to appropriately engage and release inhibition, rather than with a general executive deficit.

Cohen, Rajal G.; Klein, Krystal A.; Nomura, Mariko; Fleming, Michael; Mancini, Martina; Giladi, Nir; Nutt, John G.; Horak, Fay B.

2014-01-01

408

Criteria for dynamic similarity in bouncing gaits.  

PubMed

Animals of different sizes tend to move in a dynamically similar manner when travelling at speeds corresponding to equal values of a dimensionless parameter (DP) called the Froude number. Consequently, the Froude number has been widely used for defining equivalent speeds and predicting speeds of locomotion by extinct species and on other planets. However, experiments using simulated reduced gravity have demonstrated that equality of the Froude number does not guarantee dynamic similarity. This has cast doubt upon the usefulness of the Froude number in locomotion research. Here we use dimensional analysis of the planar spring-mass model, combined with Buckingham's Pi-Theorem, to demonstrate that four DPs must be equal for dynamic similarity in bouncing gaits such as trotting, hopping and bipedal running. This can be reduced to three DPs by applying the constraint of maintaining a constant average speed of locomotion. Sensitivity analysis indicates that all of these DPs are important for predicting dynamic similarity. We show that the reason humans do not run in a dynamically similar manner at equal Froude number in different levels of simulated reduced gravity is that dimensionless leg stiffness decreases as gravity increases. The reason that the Froude number can predict dynamic similarity in Earth gravity is that dimensionless leg stiffness and dimensionless vertical landing speed are both independent of size. In conclusion, although equal Froude number is not sufficient for dynamic similarity, it is a necessary condition. Therefore, to detect fundamental differences in locomotion, animals of different sizes should be compared at equal Froude number, so that they can be as close to dynamic similarity as possible. More generally, the concept of dynamic similarity provides a powerful framework within which similarities and differences in locomotion can be interpreted. PMID:17983630

Bullimore, Sharon R; Donelan, J Maxwell

2008-01-21

409

Bearing fatigue investigation 3  

NASA Technical Reports Server (NTRS)

The operating characteristics of large diameter rolling-element bearings in the ultra high speed regimes expected in advanced turbine engines for high performance aircraft were investigated. A high temperature lubricant, DuPont Krytox 143 AC, was evaluated at bearing speeds to 3 million DN. Compared to the results of earlier, similar tests using a MIL-L-23699 (Type II) lubricant, bearings lubricated with the high density Krytox fluid showed significantly higher power requirements. Additionally, short bearing lives were observed when this fluid was used with AISI M50 bearings in an air atmosphere. The primary mode of failure was corrosion initiated surface distress (fatigue) on the raceways. The potential of a case-carburized bearing to sustain a combination of high-tangential and hertzian stresses without experiencing race fracture was also investigated. Limited full scale bearing tests of a 120 mm bore ball bearing at a speed of 25,000 rpm (3 million DN) indicated that a carburized material could sustain spalling fatigue without subsequent propagation to fracture. Planned life tests of the carburized material had to be aborted, however, because of apparent processing-induced material defects.

Nahm, A. H.; Bamberger, E. N.; Signer, H. R.

1982-01-01

410

Grizzly bears and forestry  

Microsoft Academic Search

Timber harvesting and oil and gas extraction create ecological change beyond just the footprint of the resource extraction. These activities also create a permanent network of roads that can have lasting effects on forest ecology. Grizzly bears (Ursus arctos) suffer higher mortality when in close proximity to roads, yet bears in the foothills of west-central Alberta, continue to use these

C. L. Roever; M. S. Boyce; G. B. Stenhouse

2008-01-01

411

Bearing Lubrication Apparatus.  

National Technical Information Service (NTIS)

The patent described apparatus for lubrication of anti-friction bearings which uses the oil bleeding characteristics of grease. The apparatus consists of a housing for attachment to a bearing and a grease reservoir wherein the grease is retained in a slop...

K. H. Warren

1970-01-01

412

Evaluation of residual clubfoot deformities using gait analysis.  

PubMed

Gait analysis was used to evaluate 15 patients who had previously undergone clubfoot surgery. Because six patients had had bilateral surgery, 21 feet had undergone previous clubfoot surgery. Three of the operated feet had no residual deformity. In the remaining 18 feet, the reason for referral was intoeing in 13, calcaneovalgus in three, hindfoot varus in one, and supination/adduction in one. Clinical assessment and information from the gait analysis were used to establish a treatment plan. Satisfactory treatment outcome was achieved in 13 patients, one result was unsatisfactory, and one result was undetermined. PMID:7719834

Asperheim, M S; Moore, C; Carroll, N C; Dias, L

1995-01-01

413

Verification of predicted knee replacement kinematics during simulated gait in the Kansas knee simulator.  

PubMed

Evaluating total knee replacement kinematics and contact pressure distributions is an important element of preclinical assessment of implant designs. Although physical testing is essential in the evaluation process, validated computational models can augment these experiments and efficiently evaluate perturbations of the design or surgical variables. The objective of the present study was to perform an initial kinematic verification of a dynamic finite element model of the Kansas knee simulator by comparing predicted tibio- and patellofemoral kinematics with experimental measurements during force-controlled gait simulation. A current semiconstrained, cruciate-retaining, fixed-bearing implant mounted in aluminum fixtures was utilized. An explicit finite element model of the simulator was developed from measured physical properties of the machine, and loading conditions were created from the measured experimental feedback data. The explicit finite element model allows both rigid body and fully deformable solutions to be chosen based on the application of interest. Six degrees-of-freedom kinematics were compared for both tibio- and patellofemoral joints during gait loading, with an average root mean square (rms) translational error of 1.1 mm and rotational rms error of 1.3 deg. Model sensitivity to interface friction and damping present in the experimental joints was also evaluated and served as a secondary goal of this paper. Modifying the metal-polyethylene coefficient of friction from 0.1 to 0.01 varied the patellar flexion-extension and tibiofemoral anterior-posterior predictions by 7 deg and 2 mm, respectively, while other kinematic outputs were largely insensitive. PMID:20670059

Halloran, Jason P; Clary, Chadd W; Maletsky, Lorin P; Taylor, Mark; Petrella, Anthony J; Rullkoetter, Paul J

2010-08-01

414

Antident Bearing-Ball Retainer  

NASA Technical Reports Server (NTRS)

Jig prevents indentation of bearing balls by hard contact with edges of inner bearing rings during assembly. Jig is retaining ring which includes fingers that separates balls and pushes them against outer bearing and out of contact with inner bearing rings. Eliminates need for ball-retaining tabs on bearing cage.

Thomas, Larry L., Jr.

1995-01-01

415

A comprehensive analysis of gait impairment after experimental stroke and the therapeutic effect of environmental enrichment in rats  

Microsoft Academic Search

Although gait changes are considered as reliable indices of stroke severity and efficacy of rehabilitative therapies in humans, data from animal models of focal ischemia are lacking. To determine the effect of stroke on gait function in adult rats with distal middle cerebral artery occlusion (MCAO), we assessed the longitudinal changes in gait using an automated computer-assisted gait analysis system.

Yonggang Wang; Bruno Bontempi; Shwehuey M Hong; Kala Mehta; Philip R Weinstein; Gary M Abrams; Jialing Liu; J Liu

2008-01-01

416